Sun shower

Here’s a few pictures of the almost completed solar shower (made with salvaged wood). The water drains into the adjacent compost bin and also waters the fruit trees along the fence. We’ll be planting a few fruiting tropical plants to seclude the shower stall from view. The guys have yet to set the 100 feet or so of coiled, black garden hose that will heat the water. The shower isn’t intended to rival a typical indoor shower with a constant stream of steaming hot water. We figure all we need is enough warmish water to take a quick wash down to get off any dirt or sweat and maybe wash some hair (guy’s hair that is).

Soap & Water

Soap and detergent are the components in gray water, which could adversely affect plants the most. The wastewater from the shower generally contains only a small amount of soap, and has few solid residues. Special (biodegradable ) soaps can be purchased to lessen any harmful impacts on plants.

A question from a reader:

I would love to hear more about your discoveries as you use your greywater system. What soap/shampoo/laundry soap do you use to avoid salt buildup issues in your garden soils? If you use homemade, would you share the greywater soap recipes? I have seen very little information about what soaps *are* compatible with water re-use (brands, ingredients, etc), have only seen warnings about how detergents are not compatible. Even those of us who do not yet have greywater systems could help, by supporting with our purchases the companies who make the greywater-compatible brands. ~ Joanne P. ~

Thank you for your question, Joanne. First, we haven’t yet installed the Australian made Greywater Diverta. However,  for years, we have been re-using our laundry water. With the Divertawill also be able to re-use the bathroom sink and tub water. As for the kitchen, we won’t be re-using the kitchen sink water because of the food particles and other possible containments like cooking oils/fats.

Types of soaps that we do use that would be compatible for water re-use:


Homemade olive oil bar soap (or any natural based soaps)

Castile soap (e.g.Dr. Bronner’s)

Natural, no sodium lauryl sulfate shampoo (e.g. Aubrey Organics)


Biodegradable, non synthetic dish soap (eg. Trader Joes “Next to Godliness” Dish Soap)


Biodegradable, vegetable based laundry soap (e.g. Seventh Generation or Citra-Suds)

(Note you could also use a a soapless water treatment disk )

What about soaps and detergents? Are they harmful to the soil and plants?
Soaps and detergents are biodegradable, but they can present problems when gray water is used over an extended period. The main problem with most cleaning agents is that they contain sodium salts which, if present in excessive amounts, can damage the soil structure, can create an alkaline condition, and can also damage plants.
Avoid detergents that advertise “softening power,” because they will have a large proportion of sodium-based compounds. The phosphates in detergents can be good for plant growth, but unfortunately, the detergents highest in phosphates usually contain the greatest amount of sodium. If you re-use washing machine water, cut down or eliminate the amount of bleach you use and do not use detergents or additives that contain boron, which is especially toxic to plants.
When doing your household cleaning, use ammonia, or products that contain ammonia, instead of chlorine as the cleaning agent.

What precautions can I take to protect the soil from damage when I use gray
water over a long period of time?

As mentioned earlier, a great danger in using gray water is the build-up of sodium in the soil. You can discover if the sodium levels are high by having the pH of your soil tested. A pH of 7.5 or above indicates that your soil has become loaded with sodium. You can correct or avoid this problem by spreading gypsum (calcium sulfate) over the soil at a rate of two pounds per 100 square feet about once a month. Rainfall, or rotating gray water applications with fresh water, will help leach the soil of sodium and excess salts.

{Courtesy of University of Massachusetts: ‘Recycling Gray Water for Home Gardens‘}

You can use graywater from your shower, bathtub, bathroom sink and laundry. Only these sources are included in the legal definition of graywater


Don’t use graywater on or near annual vegetables, annual ornamental bedding plants, or for any planting that requires working the soil several times per season. Use graywater around perennials, trees and shrubs only, and wash your hands after working in soil irrigated by graywater.


If highs in the upper 80’s weren’t enough, the high today in the valley is expected to reach near 100 degrees!    Another hot winter’s day, no rain in the foreseeable future. The southland in on red alert as another brush fire has broken out in the Malibu area

January was America’s Warmest on Record 8.5 degrees above average!

No Comments

  1. claire says:

    great information on the usage of grey water, thankyou. I find it difficult to imagine how hot it must be there as its so cold here, and wet! yuck!

  2. Jeff says:

    Nice work on the solar shower!

    And thank your for the very complete information on safe soaps.

  3. Anais says:

    Hi Jeff,

    Thank you for the compliment. We look forward to using it!

  4. Anais says:


    The weather still continues to be hot. I had a tank top on yesterday and walked around outside in barefeet.

    Even though the warm temps sound lovely, we are going to need cooler and rainy weather soon!