Homeowners sometimes experience unpleasant odors in their household water. In many cases, the exact cause of the odor is difficult to determine by water testing; however, this publication provides a few general recommendations for treating some common causes of household water odors.

If odor occurs in all water faucets, the problem is probably in the main water supply. If it occurs only in certain faucets, the problem is likely in the fixtures or pipes supplying those specific faucets. If the problem goes away after running the water for a few minutes, the problem is somewhere in the household plumbing system. If the odor is persistent, the problem could be the water source or a combination of both the water source and the plumbing system.

Bad Smelling Water


Public water suppliers generally chlorinate water to prevent bacterial growth. Odors resulting from a chlorine addition usually go away if the water is exposed to air for several minutes. Adding chlorine to the water through shock chlorination of a well or plumbing system produces a strong bleach (chlorine) odor. The bleach smell stops when chlorine completely dissipates. This requires turning on outside faucets and letting the water run until the smell is gone. In some cases, the added chlorine may interact with organic materials built up in the plumbing system and add odor to the water. The odor should disappear after running the water for a few minutes. If the problem appears to be in your plumbing and/or well systems, then your entire water system should be flushed, preferably by a licensed well technician.

Sulphur / "rotten eggs"

Generally, a rotten egg (or sulfurous), decayed or sewage-like odor in household water is a result of bacterial activity, which can be due to:

  • Bacteria growing in the drain: This is the most common cause of these types of odors. Over time, organic matter such as hair, soap and food waste can accumulate on the walls of the drain. These deposits serve as a food for bacteria to grow. The bacteria can produce a gas that smells like rotten eggs or sewage.

  • Bacteria growing in the water heater: Bacteria growing in the water heater can also produce a rotten egg or sewage smell. Frequently, this occurs if the hot water is unused, if the water heater is turned off for a significant period of time or if the thermostat on the heater is set too low. Generally, the bacteria that produce this problem are not a health threat; however, the taste and odor can be very unpleasant. 

  • Bacteria growing in the well: If problems with the drain or water heater are ruled out, the odor may be coming from the water source. Do not use the water because it may contain harmful bacteria.

What can we do for you?

Contact us today to book a free estimate. Our professionals will assess your water, and suggest the most water filtration system that suits the size of your household and budget. Feel free to contact us today.

Canadian Water Inspection Services Ltd.
P.O. Box 250 - Station Main

Manotick, Ontario, Canada
K4M 1A3

(613) 491 5550


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