Q: The last few weeks, when I do a load of laundry, the water that is discharged smells like rotten eggs. I don’t think the odor is coming up from the drain, because that doesn’t smell. I have always cleaned the machine according to the recommendations, but when I do this now, it doesn’t help. Subsequent loads don’t trigger this smell, just the first load. Do I need a plumber or repairman?

A: You didn’t say whether you have a front loader or a top loader.

If it is a front loader, I’d guess that the smell might be coming from built-up bacteria around the sealing. You may have to clean it after the last load each time, so there is no buildup. We have a Bosch front loader on which we spent more than twice the cost of a top-loader, and have not been pleased with it. We do leave the door open when it isn’t in use, to ensure that the interior, as well as the door boot seal, dries out each time. I think the biggest problem we are having with it, however, is common to all front-loading washing machines.

Periodically, my wife notices that some of her clothes are stained after washing. She runs the machine empty using Affresh washer cleaner. That seems to solve the problem until the next time. I’d still call a plumber to check the drain. It may not be the source of the odor, but you never know.

Q: My hardwood floor seems to be warping on opposite ends. I can see it and feel it when I step on it.

Since I was going to have them refinished anyway, I called for a couple of estimates. The first contractor said it was called cupping, caused by some type of moisture. He said it would come out after refinishing.

The second one said it would go away in a few months, and refinishing would have to wait until then.

How can I find out if there is moisture underneath?

A: I think the first contractor is correct in his analysis of the problem, but believe that the source of the moisture needs to be identified before you spend the money to refinish those floors.

The second contractor is, in a sense, also correct if he is suggesting that the common cause of cupping — high relative humidity — is the reason for the problem.

Floors are cupped when wood curls up and the edges of the board are higher than its center.

When I find that lumber I’m using in a woodworking project is slightly cupped because it was not dried completely, I run it through my thickness planer to see if I can solve the problem.

Obviously, you can’t do that with a floor that already has been installed unless, as you refinish it, you sand the cupped portions even with the rest, which is what the first contractor is suggesting, or so it seems.

Yet, what caused the cupping in the first place? I assume the contractor believes that there might have been a moisture issue causing the cupping, and that somehow it has gone away, and all he needs to do to correct the problem is to sand it evenly.

The second contractor, on the other hand, believes the moisture problem hasn’t yet done its worst, so he wants to wait until it is no longer an issue, and then sand the floors evenly, eliminating the cupping.

It is very difficult for someone not having seen the situation firsthand to reach a conclusion. If the floors were installed when the relative humidity was low, they could cup when it was high. Unfortunately, they won’t “uncup” if the humidity drops, so sanding the floors evenly would be the obvious fix.

If the moisture causing the cupping is, say, from a leaking pipe or sweating ductwork in the basement beneath the floor, no amount of sanding will fix the problem permanently. Have a plumber take a look.

If the room gets damper in warmer months but is dry in colder months, then you’ll have to look into ways of getting a consistent relative humidity that won’t cause warping. Flooring manufacturers recommend maintaining indoor temperatures between 55 and 75 degrees and indoor relative humidity between 35 percent and 50 percent year round.

You’ll need to figure this out.

‘Smart meter’ answer

At long last, there is an answer to why a reader’s newly installed “smart meter” reported normal usage for one or two days, then surged for the next day or two — following no particular pattern.

Oddly enough, the answer came to me the week after I first published the reader’s inquiry, but until the investigation was completed, I didn’t know that it was correct.

“We have since found out that we had a leak in our well,” the reader writes.

“Who would have thought that the well pump running 24 hours a day could almost double our electric usage?”

Since the website is still not showing accurate usage, the reader is waiting for her next bill to see the difference, “but I’ve been told by a Peco representative that usage has gone from 45 to 48 kilowatt-hours per day to under 30 per day, and that’s with the air conditioner running.”

The correct answer, by the way, was submitted by Charles Ulmann of West Chester, Pa., who was my sophomore-year college roommate, and, obviously, still as sharp as a tack.