- 1). Calculate your home's production of graywater. Graywater includes the waste water from showers, bathroom sinks, baths, washing machines and other nontoilet sources. Before you add in the water used in your kitchen, check with your municipality. Some allow you to use water from the kitchen sink in a graywater system, but others do not, especially if you dispose of food down the drain. You may have to consult a professional plumber to get a reliable estimate of the number of gallons of graywater your home produces.
- 2). Look for the main plumbing stack in your house and install a parallel stack for graywater. On the main plumbing stack, cut the drains that carry graywater and cap the ends. Connect the graywater drains to the new stack and run the stack out of the house beside the main waste drain.
- 3). Check with your municipality for regulations concerning the size and type of graywater tank for your volume of graywater and whether untreated graywater may be used to flush toilets. Get the corresponding tank size and install it in the ground. A 1,000-gallon tank is common. Septic tanks are often used to contain graywater.
- 4). Connect the new graywater drain pipe to the tank. Check on treatment options in your area and install filters, aerators or use biological cleaning methods such as a pond. Install a pump in the tank or in the collection tank after treatment. Run a pipe from the pump into the basement and connect to a pressure tank if you want to re-use the graywater for toilets. Use the pressure switch on the pressure tank to switch the pump on and off. Connect the graywater supply to the toilet supply lines. Run a pipe from the pump to a lawn watering system if the graywater is to be used for watering. Run a pipe to perforated, underground pipes if the graywater is not going to be used.
Source...