Mother Earth News Blogs > Green Homes

Green Homes

Building for the future, today – combining the best of historical wisdom and modern technology.


Using Rainwater in the Laundry Room

Back when every home had a wooden barrel stationed below the rainspout, our grandmothers knew rainwater was a must for washing hair. Grandma probably even knew why water falling from the sky felt better than that pumped from the ground. Admittedly, I didn’t know the benefits of cleaning with rainwater until going off-grid with my laundry duties.

1937 laundry ad

When we tested our well water for impurities, the only bad mark we received was in that our water was extremely hard – containing heavy calcium and magnesium mineral deposits. So what, I thought. Well, as it turns out, while hard water is safe to drink, it interferes with every cleaning process because it does not dissolve soap. More soap (or, worse yet, chemical detergents) and hotter water are required to get clothes clean in hard water, neither of which appeals to my frugal, environmentalist nature.

Below is a map depicting water hardness prepared by the United States Geological Survey from rivers, creeks and streams tested in 1975. The more milligrams per liter, the harder the water. Hardest waters (greater than 1,000 mg/L) were measured in streams in Texas, New Mexico, Kansas, Arizona and southern California. Water from drilled wells is almost always harder than that taken from surface rivers.water hardness map

I learned in my 1909 copy of “Household Discoveries” a simple test for discerning at home whether water is fit for laundry purposes:

Test for Water Hardness

Simply dissolve a dab of good white soap in rubbing alcohol. Put a few drops of this mixture into a glass of water. “If the water is pure, the soap solution will be dissolved and the water will continue limpid, but if it is impure the soap will form into white flakes which will tend to float on the surface.”

To test this, I used two glasses of water – one from our drilled well and the other from the stock tank below the rain gutter. The soap disappeared immediately in the rainwater, but never dissolved or made suds in the hard water. After an hour, the well water glass also had a scummy ring on top.

water hardness home test

For years, I accused my electric washing machine of doing a second-rate job of cleaning our clothes. Who would have thunk it was merely a water issue? Now that I wash with rainwater, our laundry is no longer crispy-crunchy or besmirched and grey.

Using Rainwater in Electric Machines

Before actually going off-grid, I ran a garden hose from the rain tank outside to our electric washing machine in the basement just to see if the machine would launder better. It did, and I no longer had to add borax, washing soda or vinegar to the rinse cycle. While these additives are natural and relatively inexpensive, it is one more step to perform (and remember before the spin cycle ends).

For such a system to work, the rainwater source must be higher than the washing machine to gravity-feed the water. Or, a pump must be installed. Elaborate plans are available online, although the simplest (and most labor intensive) is to pour buckets of rainwater into the machine to fill it. Depending on the machine size, this could be 15 gallons per cycle.

“Household Discoveries” lists several ways to soften water, but also acknowledges that rainwater is absolutely best for cleaning anything, even without soap. In case of drought when a sufficient supply of rainwater cannot be obtained, however, here are some old-time methods for softening water:

To Soften Hard Water

“Bring the water to a boil and expose it to the air, which may be done by pouring it from some height into a tub or other vessel, and afterwards letting it stand overnight.

“Or boil it with the addition of a little baking soda, and afterwards expose it to the air.

“Or place a quantity of clean wood ashes in a tightly closed woolen bag and immerse the bag in a tub of water. The required amount of ashes can be ascertained by experiment.

“Or use chalk, which may be put into the spring or well or used in a tub or bucket, the proper amount depending upon the extent of the impurities, and to be determined in each locality by experiment.

“Or add a small quantity of borax or potash or soda lye, but care must be taken not to use too much, as otherwise the alkali they contain will injure the fabrics.

“Or add 1 to 2 tablespoonfuls of quicklime to each tubful of water. Slake the lime with a little warm water, stirring it to a cream, pour it into a tubful or boilerful of water, and let stand overnight or long enough to settle to the bottom. Pour off the clear water, taking care not to disturb the sediment.”

These water-softening tips make collecting rainwater much more appealing, don’t they?

Girls with laundry basket

Rainwater's Cleanliness

We do not live in an industrial area or have large tree limbs overhanging our roof, which is metal.  As such, we have only an ordinary mesh screen over the rain tank to keep out bugs and other debris.   If the roof is asphalt or other airborne contaminants are a concern, the first few gallons of rainwater can be diverted away from the cistern (referred to as first flushing). 

Where pollution is heavy, the water can also be filtered. A free-standing drip filter such as the Katadyn Drip Gravadyn can be easily installed in a rainwater harvesting system.  And here is information about an old-time rainbarrel filter.

Rainwater Collection Resources from Mother Earth News

MOTHER EARTH NEWS has many wonderful articles about collecting rainwater. These were useful to us when we set up our own “cloud juice” system:

1. Build a Rainwater Harvesting System

2. Build a Rainwater Collection System

3. Harvesting Rainwater: How to Make a Rain Barrel

4. A Better Rainwater-Harvesting System

Photos by Linda Holliday, U.S. Geological Surveys, "Household Discoveries" and National Archives.

Linda Holliday lives in the Missouri Ozarks where she and her husband formed Well WaterBoy Products, a company devoted to helping people live more self-sufficiently off grid, and invented the WaterBuck Pump. Read all of Linda’s MOTHER EARTH NEWS posts here.


All MOTHER EARTH NEWS community bloggers have agreed to follow our Blogging Guidelines, and they are responsible for the accuracy of their posts. To learn more about the author of this post, click on their byline link at the top of the page.