This doesn’t sound like much, but over one month this amounts to over 1,350 gallons per person.
In a new house, with new appliances and plumbing fixtures, this figure may drop to about 25 gallons per day, or 750 gallons per month.
How much graywater do you produce?
As an example, the national average shower usage per person per day is 11 gallons. Yet the average shower using hi flow shower heads (5gpm) is 35 gallons, and low flow is 20 gallons.
Combining the two statistics above would mean the average American showers every 2-3 days!
Practical Graywater Re-use
Kitchen and lavatory water is best left for the blackwater waste pipe network. Lavatory (basin) water is in most cases does not provide enough water to justify the connection cost, and in any case provides additional water flow to help flush the blackwater pipe system.
In a rural situation (i.e. a septic system is used), kitchen water can be used (subject to local regulations), IF the following occurs:
- A grease trap is installed between the kitchen sink and the graywater system. This ensures food scraps, fats and oils are not irrigated in the garden. In addition to containing high bacteria levels, the significant quantity of fats can create an impervious barrier within the top soil.
- The dishwasher does not empty into the kitchen sink waste, because the detergent is too caustic.