Gray Water




Gray water systems for homes is a simple but effective use of a natural resource we must try hard to preserve.

Everyday millions of people wake up and take a hot shower before starting their day.

Some take an evening bath in a standard bathtub or large whirlpool soaking tub.

A couple of times a day people use the bathroom sink to wash up or brush their teeth.




Several times a week families do one or more loads of laundry depending on the size of family.

An average four person household sends well over 38,000 gallons of reusable water down the drain each year from bathrooms and laundries.

Where does all of that used water go?

If you have a septic system this water mixes with your black water (from flushing toilets) and eventually goes into the septic tank and drain fields. Possible ground or drinking water contamination could result. If you live in a municipality it might go into the sanitary sewer system.

In many parts of the country fresh water is scarce, especially during the hotter seasons of the year. Lawn watering contributes a great deal to freshwater depletion. Lower reservoirs, wells and rivers result from increased fresh water usage.

There may be a better way.




Gray water (or Grey water) systems allow homeowners to filter gray water for use in watering gardens, yards,plants and flushing toilets. Not disposing of gray water into septic systems keeps the septic tank and drain field from becoming overtaxed with fluids. In cities the sanitary sewer system also benefits from less volume of gray water to treat and process.

What are the options?

There are basically two types of gray water systems: gravity fed manual systems and package systems. The manual systems do not require electricity or pumps because they work on gravity taking the graywater to the area needed. They may require a larger yard area to install the system outside. Packaged systems require electricity but are self-contained and can be installed indoors. With each option codes and local ordinances should be considered.

Gray water explained:

Gray water is wash water. That is, gray water all waste water excepting toilet wastes and food wastes derived from garbage grinders. There are significant distinctions between gray water and toilet waste water (called “black water”). These distinctions tell us how these waste waters should be treated /managed and why, in the interests of public health and environmental protection, they should not be mixed together.

Gray water and Black water: Key differences

Gray water contains far less nitrogen than black water
Nine-tenths of the nitrogen contained in combined waste water comes from toilet wastes (i.e., from the black water). Nitrogen is one of the most serious and difficult-to-remove pollutants affecting our potential drinking water supply.

Gray water contains far fewer pathogens than black water
Medical and public health professionals view feces as the most significant source of human pathogens. Keeping toilet wastes out of the waste water stream dramatically reduces the danger of spreading such organisms via water.

Gray water decomposes much faster than black water
The implication of the more rapid decomposition of gray water pollutants is the quicker stabilization and therefore enhanced prevention of water pollution.




Leave a Reply