Laundry Detergents for Greywater

One of the questions we get the most is: which soaps and detergents are safe to use for greywater irrigation?

The short answer is that the overwhelming proportion of water to other components in greywater renders most products completely harmless. When it comes to personal bathing products (think body wash and shampoo), the concentrations found in greywater are so small that their presence is negligible. Laundry detergents, however, should be considered. Luckily, there are many eco-friendly detergent options on the market.

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

There are plenty of biodegradable options in most stores – we’ll review a few later on. Biocompatible detergents, on the other hand, are more limited and can be hard to find. Oasis and Ecos are two great brands we are aware of. These are the gold standard of greywater irrigation. They have the lowest number of ingredients and the fewest sodium compounds (none for Oasis, one for Ecos) – with no synthetic additives to speak of. Only Oasis is advertised as “biocompatible”, but they share similar compositions.

Detergents like Earth Breeze Sheets aren’t common in stores, but sheets are emerging as a more sustainable alternative to liquid detergent. Low in salts, sheets also protect the environment by eschewing large plastic containers in favor of paper envelopes – cutting plastic trash and emissions from shipping heavy bottles filled mostly with water. They’re also great for greywater (more on that below)

Finding a Detergent at Your Local Store

When you need something in a pinch, there are plenty of safe alternatives on local store shelves. Here is what to avoid:

Powdered detergent: liquid or sheets are always better than powder, which contain unnecessary amounts of salt – more on this later.
Chlorine bleach is also a no-go, as are any “whiteners”, but peroxide bleach is ok.
Highly artificial detergents such as Tide which are packed with artificial dyes and scents, as well as harmful chemicals such as alkylbenzene, borax, boron, borate, sodium perborate, and sodium hypochlorite.
Pods, microbeads, and other plastics.
Fabric softeners are not advisable, but easily replaced with softener sheets in the dryer.

This leaves us with a wide range of colorless, odorless or essential oil scented biodegradable liquid detergents available in most stores. Here, the only potential issue is salts. Salts are found in all of these eco-friendly detergents, and that’s ok. Greywater and seasonal rain are normally enough to flush out the traces of salt, and flushing the system with fresh water will solve any (rare) persistent salt build up.

Choosing a Laundry Detergent for Your Greywater System

Looking at the ingredients is always the best way to tell how good a detergent will be for greywater irrigation. Ingredient lists can be daunting, but there are a few key elements to look at when navigating the laundry aisle:

Shorter ingredient lists are better.
Salts. Those are any ingredients with the word “sodium” in them. Again, less is more.
Any of the chemicals listed above or other chemical/artificial/synthetic ingredients are bad. Anything with numbers for names is bad.
Dyes and scents.

Reviewing Detergents from a Local Store

We took a stroll through Target and looked at some of their offerings, breaking down what we found on the back labels. As you’ll see, most of the bio-degradable eco-friendly products are very similar. And the mainstream brands such as Tide, Downy, etc… look like the stock list at a poison factory.

Ever Spring (Target brand)