Irrigating with greywater

When using greywater for irrigation, it’s important to comply with local authority requirements and to ensure that the greywater is used safely.

On this page:

• local authority restrictions
• safety and health
• distribution systems

Local authority restrictions

Check with the local authority for restrictions on greywater use such as:

• minimum distance of discharge from boundaries, waterways, wells and bores, and sea
• maximum allowed daily discharge rate.

Safety and health

Greywater that has not been disinfected will contain bacteria. Greywater may also contain chemicals from cleaning products, detergents and bleaches that can contaminate the soil and kill plants. If using greywater for irrigation, avoid:

• harsh detergents, softeners and whiteners
• bleach or cleaners with chlorine
• cleaners containing boron.

Minimise any health risks:

• Do not allow greywater to pond.
• Do not spray, as this creates aerosol droplets that can drift.
• Discharge greywater below the soil surface.
• Do not use for vegetables – it is suitable for shrubs, flowers and fruit trees only.
• Do not irrigate near children’s play equipment or play areas.
• Do not irrigate plants that prefer acidic conditions.

Distribution systems

A greywater distribution system should incorporate a distribution box and branched drain network, so that water can be diverted to different parts of the dispersal area, to allow each area to rest.