greywaterhousehold

Greywater in households refers to non-toilet wastewater produced by domestic activities such as showers, baths, hand sinks, laundry, and other domestic uses. It is called greywater to distinguish it from blackwater, the wastewater that contains toilet effluent. Greywater may contain soaps, detergents, minerals, and small amounts of organic matter.

Common uses include landscape irrigation, dust control, and, where local codes allow, toilet flushing. Kitchen wastewater and water heavily contaminated with fats or food waste are typically excluded from greywater reuse programs because of higher risk of odors, grease buildup, and pathogens. Non-edible plant areas are preferred for reuse; direct contact with edible crops is generally discouraged.

Treatment and storage vary. Simple systems rely on gravity-fed filtration or settling, with optional sand filters or reed beds. More complex or licensed installations may incorporate pumps, tank storage, disinfection (UV, chlorination), and controlled irrigation systems. In most jurisdictions, greywater reuse requires separation from the potable water supply and adherence to local codes.

Safety and regulation: Potential health risks include skin and eye irritation, microbial exposure, and chemical effects from detergents. Regulations typically address system design, placement, maintenance, and prohibitions on mixing with drinking water. Permits or professional installation may be required, and systems should avoid proximity to wells or flood-prone areas.

Maintenance and limitations: Systems require regular maintenance—filter cleaning, sludge removal, and monitoring for odors, sediment buildup, and salt accumulation. While greywater reuse can reduce mains water use and wastewater generation, its viability depends on climate, soil, household water quality, and local regulations.