Irrigating Plants with Greywater

Counties have until July 2014 to implement the greywater reuse rule. Before considering greywater irrigation, contact your local health jurisdiction to make sure you are not violating local regulations.

Some plants are better suited than others for irrigation with greywater. Generally, plants that do not do well with greywater irrigation are shade-loving and acid loving plants. These types of plants are typically found in forests where acid soils predominate.

The nutrient needs of the irrigated plants should be considered and some plants may require nutrient supplements. It is recommended that homeowners who wish to irrigate with greywater consult with a nursery, landscape architect, or local cooperative extension office for more information.

Plants not suitable for greywater irrigation

Azaleas Begonias Bleeding Hearts
Crepe Myrtle Deodar Cedar Dogwood
Ferns Foxgloves Gardenias
Holly Hydrangeas Impatiens
Magnolias Oxalis (Wood Sorrel, Shamrock) Primroses
Redwoods Rhododendrons Violets

Plants more suited for greywater irrigation

Austrian Pine Bearded Iris Big Basin Sage
Burning Bush Cottonwood Fringed Sage
Honeysuckle Italian Stone Pine Junipers
Mugo Pine Native Desert Plants (many) Oaks
Rabbit Brush Roses Rosemary
Russian Olive Sedum Sumac

Other considerations

Greywater can contain high levels of salt from detergents. For soils with a high percentage of clay or in areas with less annual precipitation than 20 inches per year, periodic flushing of the soil is recommended. Sandy soils are less vulnerable to damage by salts in greywater than clay soils because they drain better. Be aware that some harmful effects are not always visible immediately and may take one or two years to appear. Discontinue using greywater if signs of stress in irrigated plants are observed.

For more information see Useful Greywater Links or contact