How to remove sediment from water

Q. Our house was built in 1980 and we are on well and septic. For the last six years, the hot water faucets run black when we return home from an extended stay (five to seven days). Cold water faucets are OK. The "sediment" can be very fine particles and sometimes irregular small flakes. They do not smear. It clears after running the faucets for a while.

The hot water does not have a rotten egg smell, but occasionally a slightly swampy smell. I periodically drain the hot water tank, and very little, if any, sediment comes out of the tank. At the same time, I treat the hot water tank with peroxide, which helps for a month or so.

I had the water tested by NTL in April 2015 (results attached). Iron and hardness were slightly high, which doesn't bother me because I grew up on well water. Also, sulfate was a bit elevated.

Over the last three years, I have replaced the hot water heater in 2015, the well pump in 2017 and the water pressure tank in 2017, just as normal maintenance (all were original). We have a water softener that was recently tested and is removing iron and hardness.

It seems to me the sediment is coming from the pipes. Is it possible that sulfate bacteria or iron bacteria is reacting and attaching to the copper pipes? Would it be beneficial to shock the well? (I have never done that.) Should I consider adding another water filtering system that removes sulfates? In general, what do you think the cause of the black water may be?

A. My expert contact suggests that even though you are not getting any odor, he is sure the issue is due to hydrogen sulfide precipitant.

He recommends you start by shocking the hot water tank with chlorine, and possibly the well. The black sediment is precipitating out in the water heater while you are away and settling out. That would explain why it is worse when you are away.

Filtration could also be an option, but start with disinfecting the source and the plumbing and then flushing things out.

Q. We have been avid readers of your column in the Daily Herald for years.

Attached is a drawing of a typical wall in an 8-by-10-foot framed utility shed that came with my son's home. The builder used it as a hobby room with heat and insulation. The attic area is also drywalled and is used for storage like Christmas trees and decorations. When you take the stuff out of the attic, the items have the musty smell of dampness.

When I dismantled the wood trim at the outside bottom of the wall and removed the bottom four inches of the foil-backed urethane board, all the wood structure was wet (water has since been diverted), but solid, except for the 3/16th-inch sheet of paneling between the urethane board and the plastic sheets installed on the exterior of the studs. Those panels were rotted at least 4 inches up from the ground and when I put my hand behind the paneling, it was wet and deteriorated on the interior side of the paneling as far as I could reach. There appears to be significant condensation between the plastic membrane and the paneling.

The insulation looks like it is in excellent shape, and I did not find any areas where it was wet. I think the DIY builder installed the paneling as the backstop to randomly hammer the nails to attach the siding. He used short nails where I found some siding just being driven into the urethane sheets. Anyway, do I get rid of the condensation and maybe the stink if I remove the paneling and plastic sheets? Then, install plywood and Tyvek to the outside, then put the siding back?

A. The mustiness may be due to summer humidity if no means of controlling it was used.

I am not clear about one of your comments. Assuming that by wood structure, you are referring to the studs and bottom (or sole) plate, how did it get wet when you found moisture between the plastic sheeting and the paneling and not on the inside face of the plastic? And how did the bottom plate and bottom of the studs remain solid if exposed to so much moisture over time that the bottom of the paneling, sandwiched between two vapor retarders, rotted away? Are the wood members pressure-treated?

You also mention that the fibrous insulation is dry? How can that be if the wood structure is so wet that the water had to be redirected?

The cross section on your sketch shows from inside out: drywall, studding, insulation (fiberglass?), plastic sheeting (in the wrong place; it should have been behind the drywall), 3/16th paneling, 1-inch foil-faced urethane board and siding nailed through it.

And what do you mean by the water having been diverted? Was there so much that it pooled?

Under these unanswered mysterious circumstances, I am zeroing on two events:

• Backsplash from roof water getting inside the structure because of a flashing problem at the joint of the siding and the bottom trim board. Your sketch does not show that detail.

• Rain penetrating behind the siding, as few sidings are waterproof, especially if not maintained in a timely fashion.

Any water driven behind the siding by wind and air pressure is trapped by the polyiso boards and works its way behind it unless the joints were thoroughly taped with an appropriate tape that will not deteriorate over time. It wets the paneling, which has no way to dry, sandwiched between two vapor retarders.

With further investigation, it will be interesting to find out if rot of the paneling is more extensive than the bottom few inches.

I suggest you remove the siding, the polyiso boards, the paneling and the plastic. Now you are down to the framing and the insulation. Check the insulation for absolute dryness and check the health of the framing.

If possible, reuse the polyiso, tape the joints and any other defects and nail 1/2-inch CDX plywood onto the framing through the polyiso.

Staple Tyvek and one of the many available rainscreen rolls over the housewrap with as few nails as possible. The rainscreen disconnects the siding from the housewrap and allows any needed drainage to take place while airing the space between the two.

Since the siding is wood, and if you were able to remove it without damage, make sure it is backprimed with a wood preservative and that all joints are also treated.

• 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.