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A positive coliform test does not always mean you must stop showering, but it does mean the water should be treated as contaminated until you know why the bacteria are present.
If the test found total coliform only, many public-health agencies allow healthy adults to shower as long as they do not swallow the water. Extra care is needed for children, people with weakened immune systems, and anyone with open wounds. If the test found fecal coliform or E. coli, or sewage contamination is suspected, avoiding showers until the problem is corrected is the safer choice. Local health department instructions should take priority because recommendations can vary with the type and severity of contamination.
What Does a Positive Coliform Test Mean?
Coliforms are a large group of bacteria found in soil, plants, surface water, and the intestines of people and animals.
Most total coliform bacteria do not cause illness by themselves. They are mainly used as an indicator. Finding them means contaminants may have a way into the water supply.
For example, coliform bacteria can enter water through:
- A damaged or poorly sealed well
- Floodwater or surface runoff
- Animal waste
- A leaking septic system
- Contaminated plumbing or storage tanks
- Poorly maintained rainwater collection systems
- Dirty filters, pipes, or treatment equipment
CDC notes that a positive total coliform result can indicate that other harmful bacteria, viruses, or parasites may also be able to enter the water.
That is why a coliform result should not simply be ignored because the water looks clear.
Total Coliform and E. Coli Are Not the Same Result
The exact laboratory result matters.
Total coliform only
Total coliform bacteria can come from soil, plants, surface water, and other environmental sources.
A positive result suggests that the water system may be vulnerable to contamination. It does not necessarily mean sewage entered the water.
For water containing total coliform, some health departments permit showering while advising people not to swallow the water. Pennsylvania's current guidance, for example, says coliform-contaminated water can be used for showering as long as it is not swallowed.
Fecal coliform or E. coli
Fecal coliform and E. coli are more concerning because they indicate contamination associated with human or animal feces.
CDC says that a positive fecal coliform or E. coli test likely means fecal material and potentially harmful germs have entered the water.
Recommendations for bathing can be stricter when fecal contamination is confirmed. Some health authorities advise against bathing or showering with fecal-coliform-contaminated well water.
If your laboratory report says E. coli present, fecal coliform present, or indicates possible sewage contamination, use another safe water source for bathing when possible and contact your local health department for instructions.
Can Coliform Bacteria Make You Sick in the Shower?
The greatest concern during an ordinary shower is usually accidentally swallowing contaminated water.
Water can also reach:
- The mouth
- The eyes
- The nose
- Cuts and scrapes
- Irritated or damaged skin
CDC advises people using water during many boil-water advisories to avoid swallowing it while bathing or showering. It recommends extra caution with babies and young children because they are more likely to swallow bath water.
The positive coliform test is also important because coliform bacteria may not be the only organisms present. The contamination route that allowed coliform into the system may also allow disease-causing organisms to enter.
When Should You Avoid Showering?
Avoid using the contaminated water for showering until you receive specific guidance if:
- Fecal coliform or E. coli has been detected.
- Sewage may have entered the water.
- The well or water source recently flooded.
- The water is under a "do not use" advisory.
- The contamination involves unknown chemicals as well as bacteria.
- You have large open wounds, burns, or serious skin damage.
- A person using the water has a weakened immune system and safer water is available.
CDC says water under a do not use advisory should not be used for bathing or any other purpose. It also advises against bathing in water that may contain sewage or toxic chemicals.
A boil-water advisory is different. During many boil-water advisories, showering is permitted as long as you avoid swallowing the water. Always follow the specific instructions issued for your water supply.
What About Babies and Young Children?
Use more caution with young children.
Children often put bath toys, washcloths, fingers, or water directly into their mouths. That makes accidental swallowing much more likely than it is during an adult shower.
CDC recommends considering a sponge bath for babies and young children during a boil-water advisory to reduce the chance of swallowing contaminated water.
If E. coli or fecal contamination has been confirmed, using bottled water or another known safe source for bathing small children is a more conservative approach until your local health authority says the water can be used normally.
What About Cuts, Rashes, and Open Wounds?
Do not expose significant open wounds to water known or suspected to be contaminated.
CDC notes that contaminated water can infect open wounds and rashes.
If showering cannot be avoided and your health authority says the water may still be used for bathing, keep minor cuts covered with waterproof dressings. For surgical wounds, serious burns, deep cuts, or wounds that are already infected, ask a healthcare professional about safe bathing.
Do Not Use Coliform-Positive Water for Drinking
Even when showering is allowed, that does not make the water suitable for drinking.
Until the contamination has been investigated and corrected, use a safe water source for:
- Drinking
- Brushing teeth
- Cooking
- Preparing drinks
- Making ice
- Washing foods that will be eaten raw
- Preparing infant formula
Boiling can kill many disease-causing microorganisms, but it does not remove chemicals, heavy metals, salts, or other nonliving contaminants.
Reviewing testing for bacteria at home helps understand which conclusions the measured water-quality values support.
A positive bacterial test should therefore lead to an investigation of the water system, not just routine boiling forever.
What Should You Do After Finding Coliform?
A positive result should be followed up rather than treated as a one-time inconvenience.
1. Check exactly what the laboratory found
Look for wording such as:
- Total coliform present
- Total coliform absent
- E. coli present
- E. coli absent
- Fecal coliform present
If you do not understand the report, contact the laboratory or local health department.
2. Confirm the result when appropriate
Sampling mistakes can sometimes contaminate a test bottle. Your health department or laboratory may recommend another sample.
Use a certified laboratory and follow its sampling instructions closely. CDC recommends state-certified laboratories for private well testing.
Do not assume the first result was simply an error, however. Use appropriate precautions until the situation is understood.
3. Find the source of contamination
For a well, check for problems such as a damaged well cap, cracked casing, flooding, poor drainage, or nearby septic problems.
For a rainwater system, inspect the whole path from the roof to the point of use. That may include the roof, gutters, screens, first-flush equipment, tank, overflow, plumbing, filters, and treatment equipment.
A first flush device diverts some of the initial roof runoff so dirt and debris do not immediately enter the storage tank. It helps reduce contamination but does not make collected rainwater safe to drink or bathe in by itself.
4. Correct and disinfect the system
The right procedure depends on the water source and plumbing.
A private well may need repair and disinfection. A rainwater system may require cleaning, correction of contamination routes, and appropriate treatment.
Do not assume that adding one filter or UV unit solves every problem. Water treatment must fit the source, water quality, flow rate, equipment limits, and intended use.
5. Retest the water
Testing after corrective work is important.
A clear-looking tank or well is not proof that the bacteria are gone. Use laboratory testing to confirm that the contamination has been corrected, following your health department's recommendations.
What If the Water Comes From a Rainwater Tank?
The same basic precautions apply if stored rainwater supplies your shower.
Roof runoff can collect bird and animal droppings, leaves, dust, insects, and other contamination. Storage tanks can also become contaminated through dirty screens, poorly sealed openings, sediment buildup, or cross-connections.
A positive coliform result means the collection and treatment system needs attention.
For household rainwater reuse, think of water quality as a whole system:
collection → debris control → storage → treatment → plumbing → intended use
For shower water, treatment must be designed for the actual microbial risk and household flow. Filters, UV treatment, chlorination, or other methods may form part of a system, but no single device should be assumed to make contaminated rainwater safe without proper design, maintenance, and testing.
If rainwater will be used for drinking as well as showering, take a more conservative approach. Potable water—water suitable for drinking—requires suitable collection, treatment, current laboratory testing, maintenance, and compliance with applicable local requirements.
Frequently Asked Questions
Can I take a quick shower if total coliform was found?
A healthy adult may be able to shower if only total coliform was detected and local health officials allow it. Do not swallow the water, and avoid getting it into your mouth. A positive result still needs to be investigated and corrected.
Can I shower if E. coli was found in my water?
Avoid using the water for showering when practical until you receive guidance from your local health department. E. coli suggests fecal contamination, so the possibility of other harmful organisms is greater.
Is coliform bacteria absorbed through the skin?
For routine household exposure, swallowing contaminated water is usually a greater concern than contact with healthy, intact skin. However, water may also reach the eyes, nose, mouth, or damaged skin, so precautions are still needed.
Can children bathe in coliform-positive water?
Extra care is needed. Children are more likely to swallow bath water. CDC recommends considering sponge baths during boil-water advisories. If fecal contamination or E. coli is confirmed, use a safe alternative water source when possible.
Will boiling the water make it safe for showering?
Boiling can kill many disease-causing microorganisms, but boiling enough water for a shower is usually impractical. It also does not remove most chemical contaminants. Correcting the source of contamination is the better long-term solution.
Does a shower filter remove coliform bacteria?
Do not assume that a standard shower filter removes bacteria. Filters have specific purposes and operating limits. A treatment system must be designed for the contaminants present, the required flow, and the intended water use.
How do I know when the water is safe again?
Correct the contamination source and follow your health department's recommendations for disinfection and retesting. A laboratory result showing that the bacterial problem has been resolved is much more useful than judging the water by appearance, smell, or taste.
