I live in the land of crawl spaces. Very few sump pumps around here due to extreme lack of basements.

Past client called this morning complaining of musty odor in basement. New construction, closed about 3 months ago. There are 3 holes in the basement floor. 2 have sump pumps installed while the third has a cover over the hole but no pump. ~4800 square feet finished space. Basement unfinished and all below grade with the exception of a stairway about 6 feet wide leading below grade to door and window.

Client had opened the window of the basement and ran a fan to draw fresh air into the basement for a while. Then he turned the fan around and blew air out the window from the basement. Then he closed the window and ran a dehumidifier. Started at 85% and has gotten it down to 45% humidity according to him. Last 3 months the weather around here has been about 90 degrees with 85%-95% humidity.

He complained to the builder about the musty odor. The builder suggested it was probably the fiberglass batt insulation giving off the odor. Huh?

He poured bleach into the sump pumps and the odor diminished and took on a slight bleach odor. Shortly thereafter the odor returned to full strength.

The one opening in the floor without a sump pump has several threaded openings which are not capped off.

My guess is that the high humidity has caused some growth of mold or mildew. Reducing the humidity is a good thing and may eventually kill off the mold/mildew.

I would think capping off the unused sump pump hole openings would limit odor and further growth but may limit the capability for water to enter the sump during high water?

I am definitely sump pump challenged. I am looking for some guidance about sump pumps in general. I am looking for suggestions to help the client better manage the moisture and odor in his basement. Any ideas?

Pics are front of house at final inspection
Blurry pic of one of the sump pump openings in the basement floor.

Attached Images

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__________________
Bruce Ramsey
Advocate Inspections
www.NCAdvocate.com

I would recommend first, Isolating the cause. Seal the sump covers so no oder can enter the basement area. Wait a few days. If no oder, yes we need to seal the covers. ALready done.
If a mold worry. Let them do the testing. No guessing.
If still a smell after the sump covers are sealed there may be a leak somewhere.
What did you smell?

Bruce, just some thoughts.

1. Are you sure it is a sump not sewage pump? It kind looks like the top of a sewage pump with no vent installed. Is there a drain system for a bathroom etc. below grade?

2. Does it discharge to the sewer or to the exterior of the foundation. Sumps must not be connected to the sewer.

3. Why so many sump pumps? Is there a moisture problem?

I'd go along with sealing all the sump lids and see if the smell goes away.

There should be two pits in newer construction. I don't know why there are 3 holes at this house. One for ground water (drain tile). This is supposed to be ejected into the yard and doesn't need to be vented. And another for house water. This goes into the sewer and needs to be vented.

Your house likely has an overhead sewer which means the main drain goes into the basement wall so a sewage pit with a pump is needed.

Attached Images

Overhead Sewer Illustration.pdf (577.6 KB, 20 views)

So the next question is. Is there a bathroom in the basement?
Or did they use a waste pump up tank for a sump pit?
Or did the listing broker take a crap in the pit because you found so many things wrong with the home.

Thank you for all the ideas and comments. I had not been to the site for several months when I posted this morning. Visited the site this afternoon.

There are 2 sump pumps and 1 future waste ejector station. The basement is roughed in for a bathroom. The water in the two sump pumps looked clear and clean. The waste ejector was the cover with 2 open holes about 1.5 inches in diamater. This station was full of water up to the openings.

The odor to me was musty and concrete. There was no evidence of water in the basement and we have had heavy rains for the last week or two.

The dehumidifer indicated 80% humidity when turned on this afternoon.

I suggested the client seal up the sumps and water station with plastic and tape, ventilate, and reevaluate in a couple of days. Depending on the results, he may follow up.

Feeling unsure about sump pumps kept me from thinking straight. The best answer was to systematically determine what is not causing the odor. What ever is left over must be the cause. Once I stepped back and settled down, a course of action became clear.

Thank you.

__________________
Bruce Ramsey
Advocate Inspections
www.NCAdvocate.com

Just a thought --

You say there's three pits in the basement, two appear to be clear water, while the third is an empty hole that would eventually house a sewage pump for a roughed-in yet unfinished bathroom in the basement?

If so.. is the basement bath venting connected to the rest of the house's venting? Could there be any way vent gasses are backtracking down the basement bath's vent, then through the drains, and out the unsealed pit?

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