Well Water Smells Like Sewage: What to Do Right Now
A sewage, septic or manure smell is different from a rotten egg smell. It can mean waste is reaching your well. Treat it as unsafe until a test says otherwise.
Step 1: Make sure it's the water
- Fill a glass at the tap, take it to another room and smell it.
- The glass doesn't smell? The drain or a dry P-trap is the source, not the water. Run water into rarely used drains and clean the overflow and stopper.
- It smells like rotten eggs? Probably hydrogen sulfide. See the rotten egg guide.
- It smells like sewage, septic or manure? Keep reading, and test.
Step 2: Test
- Total coliform and E. coli: the key safety test
- Nitrate: rises with septic and manure contamination, and is a particular risk for infants
- Ask your health department whether it offers free or low-cost testing. Many do.
Step 3: Find the source
The Wisconsin DNR suggests checking these:
- Septic system: is it working, recently backed up, or overdue for pumping? Request an inspection.
- Distance: how far is the well from the septic tank, drain field, sewer line or a leaking sump?
- Well cap and casing: a loose or cracked cap, or a casing that ends below ground level, lets surface water and insects in.
- Nearby manure: fields, barnyards or storage near the well
Step 4: Fix it
| Step | Why |
|---|---|
| Fix the source (septic repair, well cap, casing, grading) | Disinfection doesn't last if waste keeps getting in. |
| Shock chlorinate the well and plumbing | Kills bacteria in the well. Follow Penn State's procedure or hire a contractor. |
| Retest after flushing | Confirms the well is clean. Keep using safe water until it is. |
| UV disinfection for ongoing protection | Only after the source is addressed, and with pre-filtration for sediment, iron or tannins. |
Related problems
Frequently asked questions
Is it safe to drink well water that smells like sewage?
No. Wisconsin’s DNR advises not using it for drinking, cooking or bathing until a certified lab has tested it for coliform bacteria. Sewage carries bacteria and viruses that can make you sick.
What is the difference between a sewage smell and a rotten egg smell?
Rotten egg is usually hydrogen sulfide, which is mostly a nuisance. A sewage, manure or septic smell is a warning sign of possible contamination. If you are not sure, treat it as sewage until a test says otherwise.
Could the smell be from my drain instead of the water?
Yes, and it often is. Fill a glass at the sink, walk to another room and smell it there. If the water in the glass doesn’t smell, the drain or trap is the source, not your well.
What do positive coliform or E. coli results mean?
Coliform bacteria are an indicator: they show that a path exists for contamination. E. coli specifically indicates fecal contamination. With E. coli, do not drink the water unless it has been boiled, and contact your health department.
Sources
- My Water Smells Like Sewage (fact sheet), Wisconsin Department of Natural Resources
- Private Drinking Water Wells, U.S. EPA
- Protect Your Home’s Water, U.S. EPA
- Shock Chlorination of Wells and Springs, Penn State Extension
- Hydrogen Sulfide in Well Water, Minnesota Department of Health
Sources checked October 24, 2026. Found an error? Tell us and we will fix it.