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Espsom salts #749538

Asked May 12, 2021, 4:20 PM EDT

Hello, I would like to be able to recycle/reulse the "gray water" from my bath. However, I often add about 1/2 cup Espsom salts. Questions: > Is using the bathwater on outdoor plants safe? > And, would it matter if it was used for potted plants or those in the landscape? Thank you very much for your time, effort and expertise on this question/request. Appreciatively, Janet Dennis

Benton County Oregon

Expert Response

Greetings, 

Reusing bathwater for plants would seem like a sensible water conserving solution. However there are a few issues: 

According to OSU's well water program, "In Oregon, it is currently illegal to use untreated gray water.... Currently, in Oregon, gray water is classified as sewage and is regulated under OAR 340-071 (Oregon's onsite wastewater treatment system regulations). Treatment and reuse of gray water requires appropriate DEQ permits.

To treat and use gray water requires a permit which, in most cases, is prohibitively expensive. The Oregon Department of Environmental Quality is in the preliminary stages of considering changes to gray water regulations.

DEQ's graywater fact sheet covers background, basic graywater information, and permitting questions....Future changes may result in greater flexibility for homeowners to reuse gray water while protecting the health of the community. Keep checking to see if DEQ makes any further changes to graywater use regulations."

Under circumstances where greywater use in home gardens is legal, you would most likely not want to use water with large amounts of Epsom salts unless your soil is low in magnesium. According to University of Minnesota Extension,

  • "Adding Epsom salts to soil that already has sufficient magnesium can actually harm your soil and plants, such as by inhibiting calcium uptake.
  • Spraying Epsom salt solutions on plant leaves can cause leaf scorch.
  • Excess magnesium can increase mineral contamination in water that percolates through soil."

Here's a thought for simple water conservation that bypasses these issues: when running water to warm it up for a bath or shower, catch it in a bucket and use that bucket to water some plants. You could keep a bunch of houseplants watered this way and save several gallons that would otherwise be wasted every time you bathe. 

Hello Elizabeth,

I thank you so much for your very prompt and thorough response to  my question. It’s very helpful information, and I now know what I can do.

Your additional thought of conserving household water by collecting the cold while waiting for it to get warm, is always a good one. I have been doing that for many years, now, and feel that it helps and that every bit matters. Water and its conservation is and certainly will be one of our upmost concerns over the years. I have hopes that the Oregon DEQ will realize that if households are making the effort to conserve and reuse water as much as they can, that restrictions should be lifted, and support and advise for safe greywater use should be provided.

Thank you again for your help, and for the service that you provide.
With much appreciation,
Janet Dennis
Corvallis

On May 12, 2021, at 1:53 PM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied May 13, 2021, 12:35 PM EDT

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