Recently people have been asking if it’s OK to bathe in the lake or pond.  In particular people ask about using Dr. Bronner’s Soap because it is advertised as biodegradeable.  I ran across the following post on the Belgrade Regional Conservation Alliance

Watershed Wisdom –Summertime Bathing
This time of year we get a lot of visitors and long time residents who come into the office and confess, “I love to get up in the morning and bathe in the lake. Is that OK?” I don’t want to be a spoilsport but there are a lot of things that we used to do in our lakes that we have since learned were not all that good for water quality. And things that weren’t that bad when one person did it are hundreds of times worse when hundreds of people do them. The following article, written by BRCA’s longest serving board member (20 years!), Roy Bouchard, whose day job is Head of the Lakes Division for Maine DEP, originally appeared in BRCA’s summer newsletter last year.

Summertime Bathing
Roy Bouchard
Bathing in the lake was a fun summer tradition that seemed totally harmless before we started to study water pollution. We now know using soap and shampoo is not an advisable activity, particularly when and where lots of other people are doing it.

While many soaps are biodegradable, that does not mean they are harmless. Even assuming there would be rapid dilution; the localized concentrations may be high at least briefly when there are multiple bathers in the same area, together or in succession. Many soaps contain surfactants which are important for cutting oils and similar substances and making them soluble so they wash off. These are often either toxic or challenging to life in the lake, especially microorganisms and invertebrates. Soaps may also alter the pH (acidity) of the water significantly in the vicinity of their use. Deodorant soaps and dandruff shampoos often contain heavy metals or other ingredients that are harmful when multiple people are using them in an area.

Many soap labels claim “no phosphorus” or “low phosphorus”. Most soap, even “no phosphate” ones, contains some phosphorus. While several “green” products are indeed a lot better than the standard bathing soaps and shampoos in this regard, the body oil and other grime washed off bathers’ bodies, greatly aided by soaps with their surfactants, can contribute a lot of phosphorus to fresh waters.

In addition to phosphorus, body oils, and other pollutants, bathing in lakes can contribute bacteria and viruses at higher amounts than just swimming. While it may or may not be a heath issue in a given situation, do we really want to increase the bacteria numbers in lakes where others are swimming?
And many people find the thought of swimming where others have been bathing unpleasant – it makes the lake seem more of a bathtub than a lake.

So what to some may seem an innocuous activity in reality is one of the many things people do that all add up to water pollution. Everyone should know that it is not allowed under state law to intentionally introduce foreign substances (including soap and shampoo) into our waters without a permit. However, let’s not just rely on the law as a justification for saying not to do it. The reasons stated above are behind the law and why I can’t encourage people, pets, or any other kind of bathing or washing in lakes.

Summer camps and public facilities have a special opportunity and responsibility to be good stewards
of our waters and to educate not only their campers but the public by way of example. We as lake users
have our own role to play by not polluting the waterways we all share.