Guide to Soaps for Greywater Irrigation

People often ask us what cleaners and detergents are safe to use when irrigating with greywater. Here is a practical TLDR so you can make sure your plants are happy and thriving on reclaimed water.

Don’t worry too much - your plants aren’t!

Installing and maintaining hundreds of greywater systems has shown us that most greywater will not damage your plants. To the contrary, it will nourish them with water and nutrients while supporting healthy soil.

Greywater is almost entirely clean water

The overwhelming proportion of water to other components renders most products found in greywater completely harmless.

What products should I use?

Seek out cleaning products that are “biodegradable” or, better yet, “biocompatible”.

Personal bathing products

Quantities found in greywater are small enough that their presence is negligible. Epsom salts and other salt baths are an exception.

Laundry Detergents

Salts are found in most detergents but rarely cause problems. Check the ingredients and select for the fewest “sodium” compounds. Seasonal rain is normally enough to flush out excess salt. If salt build-up persists, flush the system manually by running fresh water.

Seek clear, scentless, biodegradable detergents with a minimum of sodium.

Avoid:

• Powdered detergents

• Whiteners and softeners

• Alkylbenzene, borax, boron, borate, sodium perborate, and sodium hypochlorite

• Chlorine bleach (Peroxide bleach ok)

• Pods, microbeads, and other plastics

• Full detergent guide here

Cleaning Products

When using strong chemical cleaning products, the best option is to shut the system off.

What if mistakes were made?

Accidents happen - it’s ok! If you forget to shut off the greywater system when sending questionable products down the drain, simply flush the system with fresh water.

When in doubt - shut it down!

All greywater systems should come with a shut off valve. You can always turn it off in case of doubt and turn it back on later.