Dry wells can fail as they age

Q. When I do laundry the water goes into the laundry sink and then backs right up out of the floor drain. It goes down eventually, but the entire floor is covered in water.

I have had several plumbers in to rod out the drain but the problem comes back in about two weeks. One plumber wanted me to take out a monthly maintenance agreement - meaning they would rod it out once a month.

The toilets and shower do not back up out of the drain, just the kitchen sink, the dishwasher, the laundry.

My neighbor has concrete in the drain with a pipe, about 6 inches, sticking up from the middle with a cap on it.

So, the question is - is this a village sewer problem, or mine?

A. Puzzled by your description, because you are on a city system. I called my good friend, an HVAC expert and former vocational tech teacher; he had an immediate answer: Your laundry drains into a drywell. Even though you are on city sewer, he has seen many cases where this practice is used.

Your toilets, showers and vanity sinks are on the city sewer, which is why you are not experiencing a backup when using these fixtures.

Your laundry wastewater, the kitchen sink and the dishwasher, known as gray water, are going into a drywell, and the drywell is no longer able to absorb the heavy volume of water discharged at once by the washing machine because its sides are suffering from a clog mat that renders them unable to absorb the discharge as fast as it originally did, so it backs up.

It's curious that the several plumbers who worked on the system did not mention this as a possibility and suggest locating the drywell, and dealing with it. The drywell can be enlarged or relocated, or you may want to look into tying into the city sewer system, whichever will be the least costly and the best solution for the time being.

Your neighbor's setup sounds wild. If he or she has a similar system and this is the way it was dealt with to avoid flooding the floor, it certainly is not OK and it represents a serious tripping hazard. You may want to let them know of the above.

Q. I faithfully read your column in the Daily Herald here in the Chicago area and you have answered a couple of previous questions successfully. I have a strange septic situation that no one has been able to answer.

I have a small two-bedroom, one-bath home. When using the bathroom (shower, sink and toilet) I have no problems with smell coming from the septic tank, which is located under the porch. In fact I have "tested" this fact by running my 40-gallon water heater until it runs cold, to see if water quantity is the problem. However, when emptying the kitchen sink (five to seven gallons max, I would guess) or the washing machine (quite a bit more water, of course), an awful smell is emitted. It seems worse in the winter, but does not entirely cease in warmer weather. What is so strange is water from one area in the house does not cause a problem while water from another does. And yes, I do have the tank pumped out on a regular basis.

In talking to several people, I have heard theories that it could be a blocked vent (does not seem to me to be a viable answer, but what do I know?), or a blocked or damaged clay tile in the leach field (a possibility as the entire system is 60 years old), but there has NEVER been obvious leaks or standing water in the yard. By the way, the soil we're on here is black dirt at least 4 feet deep before it turns to clay.

I am guessing that perhaps the rate of water going in and out of the septic tank may be the cause of the problem as the washing machine water is forced out by the internal pump and the kitchen sink drains very quickly, while the bathroom drains more slowly (we take showers, not baths).

Any ideas as to why this is happening and what can be done to remedy the problem? In trying to right this situation without spending the cost of an automobile, I have been looking at a product called Aero-Stream, based out of southern Wisconsin. Have you had any experience with this product? Their product claims and BBB rating seem to be incredible, so I am wondering if this might be the answer?

A. The Aero-Stream is one of a number of aerobic systems that introduce air into the septic tank to change its contents from anaerobic to aerobic, speeding the digestion of the septic tank's contents and changing its odor to a more palatable one, if there is such a thing.

These systems can make the effluents clear and able to be discharged into much smaller leach fields or, even in some cases, on the surface without much odor.

These systems are also used on ships at sea to allow for disposal in the ocean. However, they do not kill viruses in the effluent. They can be pricey, but worth investigating as a viable option in many cases, but they would not solve your problem since it appears not to come from your septic system.

As in the question above, it sounds as if you have a split system: some of the fixtures drain in the septic tank while the others, on the other side of the house, drain into a drywell for gray water.

The black water consisting of toilets, showers and vanity sinks are discharging into the septic tank while the kitchen sink and the washing machine, considered gray water, drain into a drywell.

Drywells do not generally have traps sealing any odor backup. The fixtures they serve drain straight into the well, so when a sizable load of discharge water is filling the well, a certain amount of air is forced out and back into the house to make room for the water - hence the odor.

Even though the drywell does not receive the toilets contents, there is some odor from the bacteria in the gray water. Consider having an experienced plumbing contractor check the setup and recommend the best solution, which may be to tie into the septic tank.

Q. Where do you find the brand name on insulated chimney pipe?

A. Sorry, I haven't checked this particular item on insulated chimney brands. Your best option is to ask the dealer where you buy it.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, www.henridemarne.com. Email questions to aboutthehouse@gmavt.net.