What Is A Septic Tank Pressure Test? (Perfect answer)

The hydraulic load test is used to verify that a septic system’s absorption area can efficiently receive and filter a specified volume of liquid. Things like house size and number of bedrooms determine how much water a septic system should be able to handle.


  • The test itself involves introducing a specified volume of water downstream from the septic tank to the soil treatment unit. The evaluation includes observing whether water: Flows back into the tank Surfaces in the yard Is accepted by the soil The first two findings clearly indicate problems with the system.

What is a septic pressure test?

The hydraulic load test is conducted by surcharging the septic tank with about 150 gallons of water over a 20-30 minute period, and then observing the rise of water in the tank and the subsequent draining process (tracer dye may be used to assist in observing leachfield failure).

What are the signs of a clogged septic tank?

Signs of Septic System Clogging: Water and sewage from toilets, drains and sinks backing up into your home. Bathtubs, showers, and sinks draining slowly. Gurgling sounds present in the plumbing system. Bad odors coming from the septic tank or drain field.

Does a septic tank have pressure?

A pressure distribution system is a type of septic system that uses pressure to evenly move wastewater into individual trenches. Pressure distribution systems typically consist of three main components: The septic tank. The dosing pump and pump chamber.

How do you do a flow test on a septic system?

Perform a Dye Test Pour the dye into one or more of the sinks, bathtubs or toilets. Run the water immediately after pouring the dye. Run water from one or several faucets to achieve the desired flow rate of between 3 GPM and 5 GPM. Run the water until you’ve reached the needed water volume for the test.

How do you test a septic system?

The inspector may use a dye test during this part of their inspection. In a dye test, the inspector will introduce dye into the water that is being drained to see how much of it enters the septic tank. From there, the septic tank will get pumped and the inspector will check for any backflow from the absorption area.

What is the most common cause of septic system failure?

Most septic systems fail because of inappropriate design or poor maintenance. Some soil-based systems (those with a drain field) are installed at sites with inadequate or inappropriate soils, excessive slopes, or high ground water tables.

How do I know if my leach field is failing?

The following are a few common signs of leach field failure:

  1. Grass over leach field is greener than the rest of the yard.
  2. The surrounding area is wet, mushy, or even has standing water.
  3. Sewage odors around drains, tank, or leach field.
  4. Slow running drains or backed up plumbing.

How do I clean my septic tank naturally?

You can mix about a 1/4 cup of baking soda with 1/2 cup of vinegar and 2 tablespoons lemon to make your own natural cleaning agent. The baking soda will fizz up to help get the dirt and grime in your tub and drains. It’s a great cleaner and your septic system will thank you!

What are the 3 types of septic systems?

Types of Septic Systems

  • Septic Tank.
  • Conventional System.
  • Chamber System.
  • Drip Distribution System.
  • Aerobic Treatment Unit.
  • Mound Systems.
  • Recirculating Sand Filter System.
  • Evapotranspiration System.

Can you have a septic tank without a leach field?

The waste from most septic tanks flows to a soakaway system or a drainage field. If your septic tank doesn’t have a drainage field or soakaway system, the waste water will instead flow through a sealed pipe and empty straight into a ditch or a local water course.

Do all septic tanks have pumps?

Septic Systems Rely on Gravity, Most of the Time For that to work, a pump is needed, or sometimes two pumps. If the tank is higher than the house, a grinder pump that liquefies solids will be placed in a pit in the home’s basement or crawlspace.

How do you test a septic drain field?

In order to test the overall health and liquid capacity for your leach field, it is necessary to perform a hydraulic load test. This is done by running water at a certain rate over an allotted period of time. A failure occurs when water back-drains to the source before that allotted time period is up.

What is a septic dye test?

What is a septic dye test? A dye test is what we would equate to a visual inspection: water is introduced to the system to check for seepage over the yard. As the name suggests, the inspector dyes the water so that it is easily visible if it comes to the surface.

How much is a septic inspection in PA?

An inspection without the hydraulic load test (because it is not always needed) will run approximately $350. The load test will be an additional fee of around $300. Some firms may be higher or lower. It is customary in Pennsylvania for buyers to pay for all inspections.

What Is a Hydraulic Load Test, and When Is It Used?

He is an emeritus professor at the University of Minnesota Department of Soil, Water, and Climate and the winner of the Ralph Macchio Lifetime Achievement Award, which recognizes outstanding contributions to the pumping industry. Jim may be reached at [email protected] with questions concerning septic system care and operation. According to what many of you are aware, I have been associated with a variety of educational programs and initiatives throughout the years. Undoubtedly the most significant of these is the inspection program established by the National Association of Wastewater Technicians.

The goal of this test is to verify whether wastewater is moving through the system in the manner intended by the manufacturer.

An operation test consists of the following components:


He is an emeritus professor at the University of Minnesota Department of Soil, Water, and Climate and the winner of the Ralph Macchio Lifetime Achievement Award, which honors those who have made significant contributions to their fields. He is also the author of many books. Send Jim an email if you have any questions concerning septic system maintenance or operation at [email protected] – Over the years, as many of you are aware, I have been involved in a variety of educational programs and initiatives.

This session includes a discussion of the “operation test,” which is one of the inspection processes we will explore in detail.

This corresponds to the degree of operation inspection that the program was intended to address.


The guidelines indicate that an HLT should be carried out if any of the following situations are encountered during the course of an inspection: The cesspool or seepage pit has a volume capacity of less than 24 hours’ worth of waste. A word of caution about seepage pits and cesspools: Because these systems are not permitted in the states where I work, they must be changed because they are not deemed to be treatment systems. The use of these systems is permitted in some states, either as a result of grandfathering or because of particular geology and hydrologic circumstances.

A great deal of discussion ensued on the appropriate time period, and it was ultimately determined that if the structure is reoccupied for 14 consecutive days, the system may be reevaluated and the test can be skipped altogether.


The inspector must suggest an HLT if he or she is notified that the present system would be subjected to increased daily flows as a result of increasing occupancy or a change in the structure’s usage. An HLT is not advised for absorption areas that have just been in operation for a few weeks or less than three months. Whenever a client chooses to have an HLT performed on a newly installed system, the inspector must fully explain to them what the HLT is intended to accomplish, what types of conditions it is intended to investigate, and the limitations of testing on systems that have been newly installed or that have never been used before.

Review the HLT paper if you are interested in the specific testing processes described in detail there.

Options for Checking Septic Tank Watertightness

Receive articles, stories, and videos about septic tanks delivered directly to your email! Now is the time to sign up. Septic Tanks and More Receive Notifications There are a variety of reasons to ensuring that all septic tanks are waterproof, including the following: Because of leakage from the tank, inadequately treated sewage has been released into subterranean soils and/or groundwater. Wastewater introduced deep into the soil profile has a lower likelihood of being successfully treated as it travels down through the soil profile.

A groundwater inflow has the potential to cause problems with solids settling, treatment, and storage in the tank (all of which are critical functions of the tank), as well as with the operation and performance of downstream components of the wastewater treatment system.

  • There are weep holes in the bottom of the tank. A weep hole is a hole in a precast concrete tank that is used to remove forms from the tank and prevent rainwater from collecting while the tank is being stored prior to installation. It is preferable to avoid using them, but if they are utilized, they must be properly sealed prior to installation. Many state and municipal rules prohibit the use of these devices. Inlet/outlet pipe penetrations, top-seam junction, tank top/access riser joint, tank lid/access riser joint, any damaged, badly formed place or region where the material is too thin are all examples of what you should look for.

It is possible to verify the watertightness of a new tank by filling it with water (hydrostatic testing) or by using a vacuum pump (vacuum testing). If the tank is ready to be used in either situation, it should be tested in that state. For the test, the inlets and outlets should be plumbed with the necessary pipes, which may then be connected together.

Hydrostatic testing

When conducting hydrostatic tests on plastic and fiberglass tanks, keep in mind that they get a significant portion of their strength from the soil support. Keep the backfill close to the midseam on all midseam tanks, but leave the seam itself exposed to allow for monitoring during the test. The following is a proposed technique for testing the water in storage tanks. Keep in mind that this test does not examine the tank’s capacity to sustain external pressure; this is something that has to be addressed through proper technical design.

  1. Ensure that the input and exit pipes are properly sealed with a watertight plug, pipe and cap, or other suitable seal. Pipes should be kept away from the tank in order to evaluate any pipe connections that may be problematic. If you’re testing a tank with a midseam, make sure the seam is exposed for the water test. Fill the tank all the way up
  2. Pour water into the tank’s riser to a maximum depth of 2 inches above the tank-riser seam if the tank has a riser. It is important not to overfill a two-piece tank since the top component may become buoyant if the tank is overfilled. The water level should be measured and recorded. Please wait 24 hours. The presence of any evident leakage during this period should be investigated and corrected by the use of an appropriate sealing compound. It is regarded undesirable if the test finds leaks that cannot be rectified
  3. Otherwise, it is considered acceptable. Concrete tanks should be refilled to their original level.
See also:  Where In The Port Of The Septic Tank Cover Located? (Solution found)

The following are some essential considerations while undertaking hydrostatic testing in cold areas. For starters, water is at its densest around 39 degrees Fahrenheit; water placed in a tank at 50 to 60 degrees Fahrenheit (typical of groundwater) and left in the tank overnight at freezing temperatures would cause the level of water in the tank to decrease significantly (about 2 percent , or 3 gallons in a 1,500-gallon tank). A leak in the risers will appear to be 3 gallons because of the way the water is being lost.

Assuming the water is left in the tank after the test and no one takes possession of the site immediately, a fracture in the tank may occur as a result of that particular testing procedure.

Vacuum testing

Compared to hydrostatic testing, vacuum testing of tanks takes less time and may be completed even if there is no water available on the job site. Testing should be carried out on the tank when it is in its ready-to-use condition (i.e., pipes in the inlet and outlet, risers with lids.) During this test, all pipe penetrations, manholes, and risers are airtight sealed, and a specific insert is sealed into one of the tank manholes to ensure that the tank does not leak. Via the use of a pump, air is evacuated through this insert to a predetermined vacuum level, and the measurement from a vacuum gauge is recorded.

Please keep in mind that different tank building materials (for example, concrete) have varied strengths.

Hydraulic Load Test

When circumstances are discovered in the soil absorption area during On-lot Wastewater Inspections that raise concerns about whether the soil absorption area is adequately absorbing the effluent provided to it on a daily basis, the inspector is advised to conduct a Hydraulic Load Test on the soil (HLT). According to the HLT, an absorption area can absorb and allow to enter into the soil/environment the Design Daily Volume (DDV) of sewage effluent that the prevailing regulatory body assigns to a structure in accordance with occupancy, number of bedrooms, and other regulatory considerations.

Hydraulic Load Test Procedure

  • It is not permitted for effluent to enter the absorption region while the HLT is in progress. Most of the time, the newly drained and empty septic tank may be used as an intermediate holding tank for the first two days while the HLT is being performed. It is possible that the HLT will be postponed if rain is expected for the 24 to 48 hours necessary for the test. Based on the number of bedrooms in the house, the HLT test should be completed using the Design Daily Volume (DDV) recommended by PA-DEP Chapter 73. The water delivered to the adsorption region during the HLT should come from a position downstream of the treatment tank.

Day 1

  • It is not permitted for effluent to enter the absorption region while the HLT is taking place. Most of the time, the newly drained and empty septic tank may be used as an intermediate holding tank for the first two days while the HLT is being carried out. It is possible that the HLT will be delayed if rain is expected for the 24 to 48 hours necessary for the test. Based on the number of bedrooms in the house, the HLT test should be carried out using the Design Daily Volume (DDV) stipulated by PA-DEP Chapter 73. Water that is added during the HLT should be introduced to the adsorption area from a location downstream of the treatment tank.

Day 2

  • Inspect the water level in each observation port at the conclusion of each 24-hour period, and record the results. The inspector should next add enough water to the absorption area to bring the water level up to the elevation recorded on Day 1 after the water was supplied. The volume added on Day 2 is regarded as the absorption area’s sustained daily loading volume for the remainder of the experiment. This loading volume is deemed to be larger than or equal to the DDV if the absorption area is shown to be operating adequately in this situation. A failure of the absorption area to absorb the DDV before the water elevation reaches the Day-1 water addition height results in the Inspector deeming the absorption area unacceptable since the absorption area was unable to absorb the DDV within 24 hours.

Note: If there is any doubt regarding the results from Day 2, the HLT may be performed on the third day.

When Should the HLT Be Performed?

It is recommended that an HLT be carried out whenever any of the following circumstances are detected during the course of a PSMA Inspection:

  • There have been no occupants in the building for more than 7 days. If the treatment tank, cesspool, or seepage pit has been pumped within the last 30 days, the inspection is not required. It has been less than 30 days since new gray water sources have been introduced into the system. Within the previous 30 days, there has been significant soil fracturing activity. When the treatment tank is first inspected, it is discovered that the liquid level in the treatment tank is lower than the level of the tank’s exit pipe invert, for whatever reason. There is a damaged or blocked pipe, a defective D-box, or any other problem that would cause abnormal flows to reach all or part of the system. When there is insufficient volume capacity in a cesspool or seepage pit for more than 24 hours, If the inspector is aware that the system will be tested, the system will be
  • When liquid stands in the aggregate of a gravity distribution system of an in-ground absorption area, there is less than 5 inches of dry aggregate above the liquid level
  • When liquid stands in the aggregate of a pressure distribution system of an in-ground absorption area, there is less than 3 inches of dry aggregate above the liquid level
  • When there is more than 5 inches of dry aggregate and liquid is present in a gravity distributed subsurface
  • When there is more than 3 inches of dry aggregate and liquid is present in a pressure distributed subsurface

Re-inspect and Re-evaluate

If the home has been inhabited for 14 consecutive days and the tank has not been pumped, or if the house has been occupied for 30 consecutive days after the tank has been pumped, the HLT may not be required. If the homeowner does not choose for the HLT, the system will need to be re-inspected and re-evaluated, which will cost money.

Newly Installed, Never Used Absorption Areas

An HLT is not advised for absorption areas that have just been in operation for a few weeks or less than three months.

Cesspools and Seepage Pits

On sites with cesspools or seepage pits, the HLT can be performed by assuming that the invert of the wastewater-entry pipe corresponds to the “top of aggregate” stated above.

At-Grade Absorption Areas

An observation port should be placed one foot downslope of the lower pressure distribution pipe when conducting an HLT on an At-Grade absorption region. All of the other components of the HLT remain in their current configuration.

For additional assistance contact

If you have any questions, please contact your local Sewage Enforcement Officer or County Extension Agent. Pennsylvania Association of Sewage Enforcement Officers (PASEO)4902 Carlisle pike268 Mechanicsburg, PA 17050 Phone: 717-761-8648 The Pennsylvania Septage Management Association (PSMA) is located at Box 144 in Bethlehem, Pennsylvania 18016 and may be reached at 717-763-PSMA.

Understand the Septic Inspection Process

There are certain distinctions in care, usage, and budgeting that you should be aware of, whether you’re a new homeowner with an existing septic system or considering about purchasing or building a home without sewer hookups. This document outlines three ways in which your budget will be affected if your wastewater is treated using a septic system. 1. You will not be required to budget for municipal sewer service. Because the municipal wastewater system normally processes all of the water, the cost of city sewage service is sometimes determined by how much water you purchase from the city.

If your home is equipped with a septic system, you will not be required to pay for sewer wastewater service. Many homes with septic systems also rely on wells for fresh water rather than municipal water, which means that they are more environmentally friendly.

Watertightness Testing for Septic Tanks and Grease Interceptors

Kayla Hanson, P.E., is a professional engineer. NOTE: By reading this article in conjunction with the ” Gravity Grease Interceptor Design ” narrative and completing the related online exam, you will obtain a certificate for 2 Professional Development Hours (PDHs). Please check with your state licensing board to determine the particular requirements for PDH approval. Precast concrete septic tanks and grease interceptors are built to be sturdy, long-lasting, waterproof, and resistant to a variety of environmental conditions.

However, structural design, mix design, manufacturing, curing, handling, and installation are all important considerations in the construction process.

If the pressure is maintained at 4 inches of mercury, the tank is said to have passed the vacuum test.

First things first

P.E. Kayla Hanson writes about her experience as a professional engineer. IMPORTANT: If you read this article in conjunction with the tale ” Gravity Grease Interceptor Design ” and pass the online exam related with it, you will obtain a certificate for two PDHs. It is recommended that you check with your state licensing board to determine the precise requirements for PDH approval. Precast concrete septic tanks and grease interceptors are built to be sturdy, long-lasting, waterproof, and resistant to a variety of weather conditions.

See also:  How To Look Up If A House Has Septic Tank? (Best solution)

Reduced porosity, high density, and low permeability are all characteristics of concrete that contribute to its watertightness when the water-cementitious material ratio is low.

Tank vacuum testing

During the exam, it is necessary to wear the proper personal protection equipment. It is also important to maintain a safe distance between testing employees and any pressurized tanks. The vacuum testing should be carried out on a tank that is surrounded by other precast concrete tanks. During a vacuum test, it is possible that the tank’s structural integrity would break suddenly, causing fragments of the tank to be launched into the air, creating a potentially dangerous scenario for individuals in the area.

Joint sealants must be used during the tank’s assembly.

It is also necessary to ensure that the lid or top half of the tank is in place before to starting the test. Once the empty tank has been completed, identify which tank hole will be used to attach the vacuum device to the tank. All other entry locations, including the inlet, are prohibited.

  • Obtaining a pass means that the tank’s pressure maintains at 4 inches Hg for the entire five-minute test period. Tank retest: If the pressure in the tank dips below 4 inches Hg at any point throughout the test, the tank may be retested by resetting the pressure, allowing it to settle at 4 inches Hg, and then beginning the five-minute test period. The tank must sustain a pressure of 4 inches Hg during the duration of the test in order to pass. Troubleshooting:
  • Equipment should be thoroughly inspected to verify that the connection and access ports are appropriately sealed up. Sometimes the equipment seal is at fault
  • Listen carefully for a hissing sound, which indicates that air is leaking into the tank and causing the leak. If the tank is leaking and the cause cannot be identified, spray soapy water inside the tank, reassemble and reseal the tank, and repeat the vacuum test until the problem is resolved. As soon as the test is completed, open the tank and watch for bubbles that will form at the site of the leak
  • If necessary, the manufacturer can recommend repair materials and methods for the tank prior to retesting.

Photo courtesy of the National Parks Conservation Association. The usage of vacuum testing may be utilized to confirm the watertightness and structural integrity of various precast items, such as installed manholes, in addition to proving the watertightness and structural integrity of septic tanks and grease interceptors, among other things.

Septic tank hydrostatic testing

Before the hydrostatic test can be performed, the septic tank must be built and properly sealed. The tank should be filled with water to its operational level – which is commonly taken as the effluent invert – and left undisturbed for 24 hours before using it. It is possible that some water will be absorbed into the internal concrete surface, resulting in a decrease in the water level. If required, refill the tank with water until it reaches its original level after 24 hours. After the tank has been replenished, the one-hour time limit for the test can be started.

  • Pass: If the water level in the septic tank remains consistent throughout the whole duration, the tank passes the test. Retest: If the water level in the tank drops during the period, fill the tank back up to the level it was at when you started. Once the tank has been replenished, you may start timing another one-hour test period. In order to pass the test, the tank must maintain its water level for the whole one-hour time period. Troubleshooting:
  • As long as the water level does not fall below a certain level during the test period, the tank may be repaired in accordance with the manufacturer’s instructions in accordance with ASTM C1227, and the test method may be resumed from scratch.

Grease interceptor hydrostatic testing

Before the hydrostatic test can begin, the grease interceptor must be installed and properly sealed to prevent leakage. Fill the tank with water until it reaches its operational level – often the effluent invert – and let the tank to remain undisturbed for 8 to 10 hours before using it. If the water level does not drop throughout the 8-to-10-hour period, the time of the one-hour test period may be set to commence after that. The water level in the tank may decline over the 8-to-10-hour period as a consequence of moisture being absorbed by the internal concrete surface.

a After then, there should be no additional decline in the water level, and the one-hour test period can be started at the appropriate time.

  • Failure to pass: If the water level remains constant over the whole one-hour testing period, the grease interceptor fails the test. The grease interceptor may be fixed according to manufacturer’s instructions in compliance with ASTM C1613 at any point during the 8-to-10-hour test period, and the test procedure may be redone from the beginning if the water level lowers during the 8- to 10-hour test period.

Beyond the test methods: Vacuum testing

When it comes to watertightness integrity testing, vacuum testing is a reasonably quick and simple method that makes use of conveniently transportable equipment and follows a clear approach. Because of these characteristics, vacuum testing is the watertightness testing method of choice for a large number of firms. Because the test takes very little room, it may be carried out in the yard or even on-site. Photo courtesy of the National Pest Control Association. In addition, vacuum testing is a more conservative technique to watertightness testing than hydrostatic testing and is more strict than both.

However, these factors demonstrate that precast concrete tanks are capable of delivering superior performance and strength.

Beyond the test methods: Hydrostatic testing

In the aforementioned criteria, filling the tank with water to its maximum capacity is not required.

Additionally, filling the tank up to the riser’s maximum capacity or to the top of the riser’s maximum capacity is not required. In most cases, filling the tank up to the flow line of the outlet is sufficient to meet the requirements.

NPCA Plant Certification critical section requirements

For many subterranean storage and conveyance vessels, such as septic tanks and grease interceptors, watertightness testing is both essential and helpful to their operation. Septic tanks and grease interceptors must be tested for watertightness in accordance with the appropriate section(s) of ASTM C1227, ASTM C1719, IAPMO/ANSI Z1000, or the standards set out by the authority having jurisdiction, whichever is more rigorous. There must be at least one test per year carried out and documented on an actual or mock-up septic tank created in each septic tank form utilized at the facility.

Kayla Hanson, P.E., is the director of technical services of the National Parks Conservation Association.

Hydraulic Load Test

When determining whether a septic system’s absorption area (drain field, sand mound, seepage pit, etc.) can handle the daily volume specified by the Pennsylvania Department of Environmental Protection (PA-DEP), which is 400 gallons plus 100 gallons for each additional bedroom over three, a hydraulic load test is performed. It is essential whenever the absorption area does not receive the typical amount of use on a regular basis. It is determined whether or not the home served by a septic system is occupied and in regular usage by the way the absorption area responds when it is subjected to the pressure applied by the residents.

How is a Hydraulic Load Test performed?

To execute a hydraulic load test, you will need at least two days. After taking the water level in the absorption area (rain field, sand mound, seepage pit, etc.) on Day 1, the technician begins to add clean water until the level is reached and recorded on Day 2. Water is supplied until the absorption area reaches its maximum capacity or until the full daily volume authorized by PA-DEP is injected into the absorption area. Afterwards, the technician measures and records the water level in the absorption region for the second time.

The technician measures the water level in the absorption area.

Can a Hydraulic Load Test harm the septic system?

No. The fact that water is only supplied until the system achieves its full capacity or until the PA-DEP authorized daily amount is introduced, whichever is shorter, eliminates the possibility of hurting the septic system.

Performance Evaluation Guideline – Community Development Agency

In order to determine whether existing septic systems are functional and meet minimum performance standards established by the San Francisco Regional Water Quality Control Board (RWQCB) and the County of Marin, Environmental Health Services, these inspections will be conducted one at a time on an individual basis (EHS).

The following performance criteria have been set as the bare minimum standards:

  1. There is no surface effluent present at any time, and the effluent is not released directly into ground water at any moment. Ground water levels on the property may not rise over 36 inches below the leachfield boundaries, as a result. Positive flow from the leachfield and from the septic tank with no backup to the tank or house plumbing during high groundwater conditions
  2. An adequately sized septic tank for the structure being served and it must be serviceable – e.g., access riser for maintenance
  3. And a septic tank with an adequate capacity for the structure being served and it must be serviceable. The septic tank must be watertight and made with materials that have been certified

The processes outlined below should be followed when conducting performance assessments in order to ensure consistency and completeness in the verification of the operational state of existing septic systems.

Inspection Responsibility

Inspections must be carried out by a Registered Civil Engineer or a Registered Environmental Health Specialist who is certified in their field. It is required that the persons responsible for completing the field inspection work be knowledgeable with on-site sewage disposal systems and have received particular training in the testing and inspection techniques indicated in this document.

Background Data

Prior to completing the field performance inspection, it is necessary to acquire and examine all relevant background information regarding to the property and septic system in question. Among other things, this should include information on the permit and the site plan, “As Built” drawings of the septic systems, and the findings of previous sanitary survey inspections. On the site plan, you must show where the septic tank and leachfield are located, as well as the locations of all buildings and decks, cutbank and well locations and a reserve or fail-safe area.

See also:  How Do I Know If Septic Tank Needs Chlorine? (Perfect answer)

Any proposed building that encroaches on a reserve or rail-safe area must be replaced with a new reserve area, if one has not been designated before.

Initial Site Reconnaissance

Initially, the inspector should travel around the site to identify the location of the septic tank, leachfield, and any other important components of the system that need to be verified. In addition to determining the location of the leachfield, the length of each line and the depth of the drainpipe (below ground surface) must be known in order to compare the measured groundwater conditions with the predicted groundwater conditions. This may need the use of a metal rod or the excavation of a trench.

The inspector should identify whether or whether the system contains dual leachfields, and if so, where and how they are being used.

Septic Tank Inspection

It is recommended to begin extensive inspection of the system immediately after the initial site survey has been completed.

Access Risers

The first step is to identify where the septic tank is located and whether or not permanent access risers have been built on the septic tank. If the tank is fitted with risers, make sure they are in good working order. In order to avoid groundwater and/or surface water intrusion into the septic tank, the risers should be correctly grouted to the top of the septic tank. The lids of the risers should also be securely sealed in order to avoid the passage of smells and insects into the building (e.g., flies, mosquitoes, etc.).

Any flaws in the access risers that are discovered should be reported. If the tank does not have access risers, this should be recorded, and the property owner should be supplied with information about how to install access risers, which will be necessary to do so.

Opening the tank

The septic tank lids should be cautiously removed once the access risers have been thoroughly inspected. If there are gardens or plants nearby, special precautions must be made to avoid damage and to disrupt the yard area as little as possible. Concrete lids are heavy, and silt can “cement” them in place, making them more difficult to remove. It may be necessary to use a steel bar or another suitable instrument to aid with opening the lids. To avoid infection from harmful organisms during the tank inspection procedure, staff should wear protective boots and gloves (made of neoprene) to keep their hands clean.

Structural Condition

Once the tank has been opened, the inspector should examine and probe the tank’s structural state to see whether there are any visible symptoms of cracking or other structural flaws in the tank. A steel rod is used to probe the tank’s sides and bottom with a magnetic probe. In most cases, this technique will not necessitate the removal of any water from the tank. The sanitary “tees” at the inlet and exit should also be checked to ensure that they are in good condition, that they are correctly positioned, and that they are clear of scum buildup, pebbles, root debris, and other obstacles.

Liquid Level

The amount of liquid in the tank should be measured with regard to the output pipe, not with respect to the tank itself. In a fully operating system, the level of the tank should be equal to the level of the invert (i.e., bottom of the outlet pipe – see Figure 1). It is possible that the tank is leaking if the liquid level is lower than the exit pipe. If the liquid level rises over the pipe, the leachfield is either inundated or blocked, depending on the situation. In order to determine the level of water above or below the output pipe, it is necessary to measure and record it.

Tank Capacity

The capacity of the septic tank (in gallons) should be calculated by taking measurements of the tank’s width, length, and depth (below the outflow pipe) before installation. It is therefore necessary to compare the capacity to the established water consumption and wastewater flow rates for the property. To be considered adequate, the current septic tank must have a septic capacity that is at least three times the maximum estimated daily wastewater flow rate; otherwise, the tank must be upgraded.

Return to the top of the page

Hydraulic Load Test

After that, the inspector should proceed with the hydraulic load test of the septic tank and disposal field, as necessary. According to the procedures outlined below, the test is only performed on normal gravity-fed leachfields and does not apply to systems that are powered by a pump. It is outlined in further detail in the next section how to conduct a separate test for pump systems. This test is performed by surcharging the septic tank with approximately 150 gallons of water over the course of 20-30 minutes, and then watching the rise in water level and subsequent draining process to determine whether or not the tank is working properly.

It is possible to utilize a tracer dye to aid in the detection of leachfield failure. Surcharging the tank can be accomplished by the use of a garden hose connected to the tank’s output side. The hose outlet should be left in place.

Test Procedures

The following are the step-by-step methods to be followed for the hydraulic load test:

  • Take note of the location of the static water line in the septic tank (on the output side) as a starting point for your investigation
  • To begin the hydraulic load test, fill the tank with water and begin surcharging it. Keep an eye out for any changes in the liquid level at the outflow pipe, and take a reading of the water level at the conclusion of the filling process. Most of the time, the liquid level will rise from 0.5 to 1-inch, at which point the liquid level should stable for the duration of the filling process
  • And the liquid level will return to its starting level in a few of minutes after the filling process is halted
  • Immediately upon completion of the filling cycle, the water level in the septic tank is monitored until the original level is achieved, and the time it takes to accomplish this level is recorded. In the event that the
System Rating

An overall hydraulic performance grade for the system will be issued based on the water level measurements taken throughout the test, in accordance with the parameters outlined in the accompanying Table 1. It should be stressed that these are only recommendations, and that unusual situations may arise that necessitate altering the evaluation and ranking of specific systems in some cases. A system that receives a “Failed” rating will need to be upgraded in the right manner.

Rating Septic Tank Response to Hydraulic Loading
Excellent No noticeable rise in water level during filling.
Good Maximum water level rise of about 1-inch, with rapid decline to initial level within 5-minutes after end of filling.
Satisfactory Maximum water level rise of about 2-inches, with decline to initial level within about 15-minutes after end of filling.
Marginal Maximum water level rise of about 3-inches, with decline to initial level within about 30-minutes after end of filling.
Poor Water level rise of more than 3-inches, with decline not reaching initial level within 30-minutes after end of filling.
Failed Water level rise of more than 3-inches, with no noticeable decline within 30-minutes after end of filling.

Return to the top of the page

Final Leachfield Inspection

Following the conclusion of the hydraulic load test, the drainfield area and downslope regions should be inspected for signs of surface effluent, moisture, or aromas, and if any are found, they should be cleaned immediately. It will be regarded conclusive proof of system failure if any of these circumstances are found to be present as a result of the hydraulic load test. A more thorough study may be required if the field observations of wetness are not clearly the result of the hydraulic load test.

Additional investigative work may involve water quality monitoring (for total and fecal coliforms, ammonia and nitrate concentrations), dye testing, and other types of laboratory analysis.

Pump Systems

It is recommended that the following inspection procedures be performed for systems that are equipped with an effluent pump. Figure 2 (on the left) depicts a schematic representation of a typical pump system installation for reference.


Remove the pump access cover as well as the basin lid, taking care not to allow any soil or other debris into the basin during the process. Consider any evidence of earlier pump failure (for example, the presence of scum line above the high water alarm button) and any evidence of dirt or roots into the basin while inspecting the scum and sludge accumulation. Examine the float controls to ensure that they are free to move, and look for any evident signs of corrosion in the electrical junction box (if it is situated in the basin or access riser).

Pump Test

The pump test is carried out by adding sufficient water to the basin to activate the pump “on” control and watching the system’s performance for at least one pumping cycle after the water has been added. Water should be provided in a total volume of around 150 gallons in order to approximate the same hydraulic loading of the leachfield as that experienced by gravity-fed systems It is possible to transfer water to the septic tank’s output side using a garden hose, or it is possible to feed water directly to the pump basin.

This may be performed most effectively by directing the jet of water against the inside side of the chamber rather than straight against the chamber’s outside.

Leachfield Inspection

Following the completion of the pump test, the disposal field area should be checked for signs of seepage in the same manner as it is done following the completion of the hydraulic load test for gravity-fed systems.


Upon completion of the septic system examination and testing, the inspector is responsible for replacing all access lids and cleaning all instruments before departing from the site. Cleaning and disinfecting any instruments and equipment that comes into touch with wastewater using a 1:5 bleach solution is recommended, and all contaminated rinse water should be disposed of in the septic tank.

Leave a Comment

Your email address will not be published. Required fields are marked *