We bought a farm in 2019 and spent 2020 renovating the 1987 stick built house. We moved in November 2020. Since we have lived here there is an intermittent sewage/rotten egg smell from the basement when a lot of hot water is used--only the hot water and the smell does not come from the water. There is no mistaking where it is coming from. We can have the smell completely eliminated and then start a load of laundry and take a hot shower and the smell is strong again.

We put in a vapor barrier (poly wrap with sump and drain) one week and had a bathroom/laundry room plumbed in the following week with a sewage ejection pump installed. We have had the plumbing company out four times and the vapor barrier folks here once. I have communicated several times the correlation between the hot water usage and the smell. The plumbing company, who also installed the new hot water heater, said that if there is no smell in the water, the water heater is not the culprit. They have ran a camera in the lines and smoked our lines twice. The plumbing company is now saying that it is a smell from the poly on the vapor barrier.

My question:

Can the smell be coming from the hot water heater?

We are not on well water. Everything is brand new: lines, hot water heater, HVAC. We basically live in a new house. The gas lines are copper and the water heater is propane.

I am at my wits end & checkbook end. I would appreciate any and all help!

  • 1
    They usually put a chemical in propane/gas that smells like rotten egg, so you know if there is a leak. Sounds like either a small leak or heater not burning all of propane. Poly should not have smell unless burning it.
    – crip659
    Commented Feb 28, 2021 at 19:21
  • You use water heater and is only time you get the smell, sounds like water heater is or near cause of smell. Could be someone left an egg sandwich behind heater also.
    – crip659
    Commented Feb 28, 2021 at 19:42
  • No egg sandwich.
    – KSFarmer
    Commented Feb 28, 2021 at 20:30
  • 1
    Had the same issue. The sacrificial metal anode in the water heater reacts with thing in the water. Researching found that using electric anode does not produce the action, so got one installed it, the smell is really gone. Like you, our symptom was: cold water smells fine, hold water has the smell. This put us into researching the water heater.
    – Chris
    Commented Mar 1, 2021 at 6:06
  • Chris, to be clear, the water (hot or cold) has never had an odor. I read right away that odor in the water can be resolved with a zinc alloy anode rod. Since the water has never been an issue, I haven't invested in trying this solution.
    – KSFarmer
    Commented Mar 1, 2021 at 6:46

1 Answer 1


Since you said your gas lines are copper I would guess you have a gas water heater.

If your water heater is not properly vented AND has a sufficient source of fresh air this is probably the source of the problem.

What is happening? The most common problem is insufficient make up air. We know the gas water heater requires a vent and I have never run into a no vent problem.

The cause I have found quite a few times is not enough fresh air so the exhaust vent takes the air out but then the home goes slightly negative as far as pressure. When this happens the room air is consumed and the exhaust gasses circulate in the air space leaving the foul odor you have when the water heater is running for a while.

To prove this open a window in the basement a bit if there is one or make sure there is a fresh air source to the basement to verify this would fix the problem. To make a permanent fix a fresh air source should be ducted to the water heater area and in most areas this is required by code.

Give a fresh air source a try and it will probably solve your smell problem.

  • It is possible to generate such a negative pressure that you pull sewer gas through some plumbing traps. This is especially true for some types of floor drains that don't get frequent use. When you do the window test, don't open the window more than about 1/4 inch and you may actually notice a breeze when the water heater is on. Commented Feb 28, 2021 at 20:10
  • Thank you ScienceGeyser and Ed Beal. The smell is also worse when the wind is blowing. Kansas=A lot. I'll give this a try and visit with the plumbing company about adding a vent.
    – KSFarmer
    Commented Feb 28, 2021 at 20:34
  • Another question- Can I solve this issue if I take the gas water heater out and replace it with an electric?
    – KSFarmer
    Commented Feb 28, 2021 at 21:20
  • @KSFarmer Yes, this might solve the problem if the problem is the vent. It will likely be cheaper to install a fresh air vent though. I find that gas service is often more reliable than electric. It sure is nice to get a hot shower the day after a storm knocks out your electricity and the power company tells you it's going to be three more days before they get to your area. Commented Feb 28, 2021 at 21:50
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    I have had drains in basements that did dry out and allow sewer smell in but this normally gets worse as the trap drys out. One way to keep traps from drying out if that was the problem is to add some cooking oil to the trap. The oil doesn't dry out and as long as a lot of water is not put in the drain the oil stays on top keeping the water from evaporating. It could be part of the issue but the intermittent and wind associated problem sounds more like a fresh air source is needed.
    – Ed Beal
    Commented Mar 1, 2021 at 1:52

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