{"id":2330,"date":"2021-04-11T11:31:54","date_gmt":"2021-04-11T18:31:54","guid":{"rendered":"http:\/\/support.cleanwaterstore.com\/blog\/?p=2330"},"modified":"2026-10-02T11:17:12","modified_gmt":"2026-10-02T18:17:12","slug":"how-to-tell-if-odors-from-well-water-is-coming-from-well-or-inside-the-house","status":"publish","type":"post","link":"https:\/\/www.cleanwaterstore.com\/blog\/how-to-tell-if-odors-from-well-water-is-coming-from-well-or-inside-the-house\/","title":{"rendered":"How to Tell if Odors From Well Water Are Coming from Well or Inside the House"},"content":{"rendered":"

\"Woman<\/p>\n

Water containing hydrogen sulfide gas (“H2S”) has a distinctive “rotten egg” odor, which may be especially noticeable when running hot water<\/a>. If your water smells like sulfur or sewage, the real question is where it’s coming from, your well, your water heater, or your household plumbing, since the fix is different for each.<\/p>\n

Such water can discolor coffee, tea, and other beverages and alter the appearance and taste of cooked foods. Hydrogen sulfide (“H2S”) gas is a nuisance that is not usually a health risk at concentrations typically found in household water.<\/p>\n

Hydrogen sulfide can be toxic. Usually, the gas can be detected long before it reaches harmful concentrations. H2S is flammable and poisonous. While such concentrations are not typical, if gases are released in a confined area, they could cause nausea, illness, and, in extreme cases, death.<\/p>\n

H2S dissolved in water can corrode plumbing metals such as iron, steel, copper, and brass, and exposed metal parts in washing machines and other water-using appliances. Switching to an aluminum rod in water heaters can help eliminate the odor while still providing corrosion protection.<\/p>\n

The corrosion of iron and steel from hydrogen sulfide forms ferrous sulfide or “black water,” which can darken silverware and discolor copper and brass utensils. Hydrogen sulfide can also interfere with the effectiveness of water softeners and filter systems.<\/p>\n

The First Step: Check for Odors in Cold vs. Hot Water<\/h2>\n

\"Cross-sectional<\/p>\n

Run a hose bib or tap as close to the well as possible, fill a 5-gallon bucket or other container, and notice if there are odors. A “rotten egg” smell<\/a> typically points to hydrogen sulfide gas.<\/p>\n

Manganese usually shows up as black or brown staining and a metallic taste rather than a distinct odor. A scent resembling cucumbers or sewage is usually caused by iron or sulfur bacteria.<\/p>\n

Only Smells in Hot Water? Check the Anode Rod<\/h3>\n

Run the hot water from each tap and notice if the odor only shows up in hot water, not cold. This indicates a problem with the water heater<\/a>, not your well. Iron and sulfur bacteria can interact with the anode rod in water heaters, producing hydrogen sulfide gas only in hot water.<\/p>\n

Changing the anode rod to an aluminum-zinc rod can often solve this problem.<\/p>\n

It’s worth draining your water heater at least once a year. This flushes out sediment that accumulates in the bottom and gives you an idea of what type and how much is present.<\/p>\n

Locating the Source of the Odor Inside the House<\/h3>\n

If you’re experiencing a rotten egg odor, start by checking your water heater, it’s the most common culprit. If the odor is only present in hot water, the magnesium anode rod is likely reacting with naturally occurring sulfates to produce hydrogen sulfide gas.<\/p>\n

Next, inspect your plumbing system, including pipes and fixtures, for signs of corrosion or mineral buildup. Also check your water softener, since it can sometimes contribute to the growth of sulfur-reducing bacteria. Working through these potential sources systematically helps you pinpoint the origin before you spend money on the wrong fix.<\/p>\n

Sulfur Odor in Pipes After Installing a New Treatment System?<\/h3>\n

Add a cup of bleach to the pipes after installing a new softener or whole-house filter, and flush the water heater and household cold water pipes with some bleach to eliminate the odor.<\/p>\n

Odors can still develop in the pipes because of biofilms, even when there’s no odor leaving the new treatment system itself. This tends to be worse in sections of plumbing that don’t get used much.<\/p>\n

Introducing a small amount of chlorine (laundry bleach works fine) and letting the water sit for a couple of hours sanitizes the pipes and helps prevent odors from developing in them.<\/p>\n

\"Installed<\/p>\n

Water Heater Odor Only? Sanitize It Directly<\/h3>\n

If the odor is primarily in hot water, the water heater needs sanitizing. Turn off the water pressure to the water heater, add 1 cup of chlorine bleach, and turn the water back on.<\/p>\n

If you have a prefilter housing, add the bleach there. If not, remove the inlet flex pipe and drain some water out of the water heater. Run hot water in the home for a minute to mix the chlorine bleach in, then turn off the water. Let the water heater sit for 2 hours, then run the hot water until it’s clear. Severely fouled water heaters may need this repeated.<\/p>\n

If the odor returns, you may need to remove or replace the anode rod entirely.<\/p>\n

(Learn more about water odor<\/a>.)<\/p>\n

Sulfur Odors on Upper Floors Only?<\/h3>\n

In some cases, the smell is worse on upper floors because the gas rises and shows up at fixtures higher in the house.<\/p>\n

The fix is to shock chlorinate the household pipes: add enough bleach to reach a 100 to 200 ppm chlorine residual, then let the chlorinated water sit in the pipes overnight \u2014 12 hours minimum. Note that this is a pipe flush, not a well shock; disinfecting the well itself uses a higher 200 ppm target and is covered in our shock chlorination guide.<\/p>\n

Repeat the process if the odor disappears but returns within a few weeks.<\/p>\n

An inline filter housing makes this easier to do repeatedly. With a spindown filter<\/a>, you can turn off the water to the house, unscrew the filter, and add chlorine bleach or peroxide directly.<\/p>\n

\"Hydrogen<\/a><\/p>\n