Recent News and Articles on the Keywords: reverse osmosis + water filters + water  Related to the article below (Last Update: 8/5/2008)

Reverse-osmosis water filters: Is the glass half empty or full?

Q: We inherited a reverse-osmosis filter at the kitchen sink in the house we bought some time ago. I am curious about how important/relevant this is. We are on public water.

A: This question completely depends on whom you ask. The people selling, and many others using, water filtration devices swear by them. Still others might swear at them. Looking at both sides, the water tastes better, or at least people come to think it does, and it is indisputably cleaner.

Reverse osmosis is such a perfect filtration system that 98-99 percent of all trace minerals and other impurities are filtered out, leaving pretty much the water molecules only. But some of these minerals and fluorides are beneficial. Mineral supplements are recommended by purveyors of these machines.

A bit of regular maintenance is required, and the black scaly mess I saw recently inside a one-year-old filter reminded me of the innards of a water heater. Yuck. The required maintenance can cost $100 or more per year.

Knowing we have some of the cleanest and best-tasting public water in the world here, I would be inclined to use reverse osmosis in my home to protect against my own aging plumbing system more than the public water supply. Older galvanized steel plumbing that doesn't get regularly used would be one example. Rust flakes don't go well with my chai tea.

A related item: Pre-1986 copper plumbing supply lines. That year, lead-based solder was outlawed for use on water supply piping as it tends to slowly leach into the water over time as it sits in the pipe. Lead can be extremely harmful, especially to small children. Federal laws also went into effect limiting the amount of lead used in plumbing fixtures at about the same time. With lead-soldered plumbing systems, simply running the water for 20 seconds or so before taking a drink (until it runs cold) will help flush out and reduce lead levels. To tell if you have lead solder at joints, you can pay for a test kit ... or, take the edge of a quarter and rub it on the joint. A dull finish is a lead joint. If it brightens up, it is not.

And never, ever use hot water from these systems for drinking.

Q: We have a newer house (1995) with a terrible problem with brown/black edge stains on our carpet. It is so bad in places that we need to replace the carpet, but are concerned it will come back again. What can be done?

A: This theme pops up again and again with readers, so I think it's worth revisiting. Negative air pressure in newer, tighter homes forces air to come into the house from the crawlspace, the attic, under the walls, and any other place it can. The incoming air is filtered by the carpet and turns it black. Older houses built before the middle '80s don't suffer this, since air leaks in from many different places (doors, windows). Newer houses with darker colored carpet may have the same issues, but the color of the carpet hides it.

Negative pressure is most commonly the result of leaking heat ducts, non-ducted, non-sealed cold air return plenums — using wall cavities rather than pipes to move air (especially under stairs), and leaks out the top of the building. Air generally leaks out the top of the building, while air comes in at the bottom, unless pushed by a fan.

To treat the symptom rather than the cause, pull the carpet up and silicone the wall to the floor where the staining occurs. Treating the root cause means checking out the biggest likely contributors: heat ducts and boots, holes in the tops of walls in the attic, missing exhaust fan louvers, dryers, older unsealed recessed lights, and so on.

Q: I have a tar and gravel roof. It has a moss problem. How important is it to remove the moss? Can the moss eat through the surfacing material?

A: Moss holds moisture against the roofing and can in fact attach itself to and deteriorate the surfacing, as you suspected. It tends to hold water against the surface, preventing it from drying also. Gravel used for protection is great in a dry climate, but it doesn't work well where heavy tree debris or moss is an issue. (This could mean anywhere west of Cle Elum, right?)

Cleaning the gravel is difficult to impossible, especially when it is partially imbedded in the tar. Setting up a gravel cleaning and filtering operation on your roof is not practical, so I would occasionally dump a water, bleach or TSP (a heavy-duty cleaner) and dish-soap cocktail on it once in awhile to keep the moss in check.

Darrell Hay answers readers' questions. Call 206-464-8514 to record your question,