One Shower, Hold the Shampoo: Nitty Gritty

BATHING IN CHEMICALS: Products we use at home often end up in rivers and lakes, hurting fish H-Huynh/Flickr

How much does it benefit the environment if I skip a shower once, twice or three times a week? What about replacing shampoo and conditioner with baking soda and apple cider vinegar?

SueAnne Ying, ’02, Castaic, Calif.

While researching this subject, I was surprised to find sodium laureth sulfate (SLES) as one of the top ingredients in my shampoo, body wash, face wash and dish detergent. SLES is produced in large quantities industrially, is cheap and stable, and is added as both a foaming agent and strong detergent to wash oils away. SLES is synthesized by reacting coconut oil with acid; some clever marketers will therefore label it as a naturally derived product, although it is not a naturally occurring chemical. Sodium lauryl sulfate (SLS), which SLES is derived from, was first developed as an industrial degreaser and is widely used to irritate the skin as a standard to compare other potential skin irritants.

Skin Health

Recently there has been a growing backlash against SLS and similar chemicals. There is no evidence that SLS is carcinogenic, contrary to marketing claims by natural product companies, although it is a strong skin irritant.

We often take our skin’s health for granted, and may even treat it like a simple, physical barrier to the environment. But in fact, our skin is a large, sensitive and complex organ. The skin’s water content, humidity, slightly acidic pH, and lipids and oils allow it to be an effective, sophisticated defense against physical, biological and chemical threats. Skin damaged by constant washing can become compromised, and hence some washing may do more harm than good. In fact, each person has a signature host of microfauna on her skin, which defends the skin against pathogens, and excessive washing can knock out the balance of naturally occurring microorganisms. Therefore, there is no sense in trying to remove all bacteria from our skin: It is not only impossible, it is undesirable for healthy skin.

Chemicals in Homes and the Environment

Water used in our homes is usually collected at a municipal wastewater treatment plant. Chemicals from pharmaceuticals and personal care products (PPCP) also end up in that wastewater, and are increasingly being found in the environment after release from water treatment facilities. These chemicals can come from medical residues that are excreted through urine or feces; when externally applied chemicals are washed off in the shower; or when unused drugs are flushed down the toilet. We do not know the environmental consequences of many of the PPCP chemicals currently being released, but studies are underway.

Image: Daughton C.G. (2007)
Check this link from the EPA for the full image of how PPCPs are distributed in the environment.

Even at very low concentrations, some chemicals can disrupt the endocrine system of fish, and cause deformities such as missing fins and organs. For example, triclosan is an antimicrobial chemical that is found in toothpaste, shampoo, soap, and even in antimicrobial cutting boards. Triclosan can be toxic in aquatic ecosystems, even when it is safe for human health, because animals and plants live in the water, and may be exposed to these chemicals during their whole lifespan. Also, triclosan tends to stay in the fatty tissue of organisms and can accumulate in fish and other organisms to several thousand times more concentrated than it was in the water. While wastewater treatment plants will remove most of the triclosan in the wastewater stream, a low concentration of triclosan has been detected in rivers and streams throughout the United States.

PPCPs of particular concern for the EPA are:

  • antibiotics and antimicrobials
  • estrogenic steroids
  • antidepressants
  • calcium-channel blockers
  • cholesterol-reducing drugs
  • anti-epileptic drugs
  • musk fragrances

What You Can Do

We can reflect on our hygiene practices and consider whether they’re sustainable or even practical. The amount of water and chemicals we use in the bathroom do add up. Below is a table to estimate your daily water usage. Multiply this number by 365, and you’ll get the amount of water used in a whole year. Put another way, if you skip three 10-minute showers a week, with a showerhead that uses 3 gallons per minute, you’ll save 90 gallons of water per. This previous SAGE column provides more details on doing a complete assessment of your home water use.


Average Rate

Usage per Day

Total Usage (gallons)


3 gallons per minute

10 minutes



15 gallons for 1/2 tub



Running faucet

2 gallons per minute

10 minutes


Clothes washer

20 gallons a load

1 load



3 gallons per load

1 load


Lawn watering

5 gallons per minute

20 minutes



2 gallons per flush

9 flushes


Total Usage per Day



This table shows how water usage for an average person in the North America would be distributed in one day. The calculations are performed by plugging in an estimated time or number for each water usage activity under the Usage per Day column, multiplying this by the Average Rate, and calculating the Total Usage; the numbers under the Total Usage column are added to get the Total Usage per Day at the bottom of the table. To customize these calculations for your own usage, if you water the lawn for 20 minutes every other day, then the average Usage per Day is 10 minutes, and the adjusted water use for lawn watering is 50 gallons per day instead of 100 gallons per day.

Another important way of helping the environment is to be conscious of the chemicals used in the bathroom. Antimicrobial agents are not needed in consumer products, so avoid products that contain triclosan. When antiseptics are needed to clean kitchen and bathroom surfaces, bleach and hydrogen peroxide are very effective, and are preferable to using antimicrobial agents, such as triclosan and triclocarbon. Widespread use of antimicrobial chemicals can allow strains of bacteria that are resistant to these chemicals to proliferate, which reduces the efficacy of the antimicrobrial chemicals. Drug resistant bacteria are hard to kill, which can be a major problem in hospitals with many very sick patients. Bacteria are much more likely to develop resistance to antimicrobial chemicals than bleach and hydrogen peroxide. Another important step is to not unnecessarily flush unused drugs down the toilet. The Office of National Drug Control Policy and the FDA have a specific list of drugs that should be flushed down the toilet if unused or expired, to prevent unintended or unprescribed consumption by children, pets and other adults. If the drug is not in the list, the FDA recommends searching for local drug take-back programs, which can be found online. Here is a list of locations in the Bay Area; your local pharmacy should also be able to help. If a local drug take-back program is not available, then the FDA recommends that you take out the drug from its original container and mix it with something nasty, like kitty litter or used coffee grounds, seal it in a ziplock bag, and dispose of it in the trash.

Simple. We all know it’s easier to clean one room than the whole house; same goes for cleaning up the environment. It’s much easier to dispose of chemicals correctly than to spread it across the country and try to clean up our rivers and streams after they have been contaminated.