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Healthy Home Basics - Plumbing and Moisture

By HHI Staff

From The Healthy House Answer Book: Answers to the 133 most commonly asked questions. Questions 48-54.


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48. Should I use metal or plastic water pipes in my new house?


Plastic water mains are now widely used by utilities, and they’re also common in many new houses. They tend to be easier and less expensive to install than metal pipes. Many plastic pipes use both a toxic solvent-based cleaner and cement to fuse the pipe and fittings together. While these are very noxious, they’re so volatile that they outgas quickly—usually within a few hours—if there’s plenty of extra ventilation.


When water moves through new plastic plumbing lines, many sensitive people report a plastic-like taste. This occurs if contaminants are being released into the water, either from the pipe itself or from the cleaner or glue.


While you can’t do much about what your water utility uses for underground water mains, we prefer to use copper for supply lines inside houses. In the past, lead-based solder was common. But today, Federal regulations forbid the use of lead in plumbing solders. Galvanized-steel piping is also relatively inert, but it’s usually more expensive than copper.


Drain pipes are bigger in diameter, making copper drains expensive. Therefore, we often recommend using plastic for these. The plastic really doesn’t outgas very much into the air. But to minimize outgassing, we buy the pipe and fittings early in the construction process and let them air out before they're installed. Then, when the cleaner and glue are used, we stay away for a while and provide extra ventilation until everything has aired out.


Because plastic drains are almost always inside wall or floor cavities, they’re rarely exposed directly to the living space. That means, they usually aren’t an outgassing problem. Still, just to be extra safe, we often recommend to sensitive people that plastic drains be wrapped with household aluminum foil before the wallboard is installed over them.


49. Do you believe all houses need a water filter?


That’s a tough question to answer. The goal isn’t to obtain pure H2O, because pure H2O can be tasteless, and its very purity makes it aggressive. Aggressive water will dissolve and grab minerals from whatever it touches. If you drink aggressive water, it can actually pull minerals out of your body—minerals you need for good health. So, you don’t want to purify water too much.


Before you think about filtering at all, you should determine how polluted your water is. If you’re on a public water utility, it should be able to give you a water-quality analysis which will tell you what contaminants are in the water. If you’re on a private water supply (well, cistern, or pond), you’ll probably need to have your water tested by a private laboratory. Many different contaminants are possible, and testing for all of them can be expensive. So, you might ask someone at a nearby utility which contaminants are most likely in your geographic area. They can also usually recommend a testing lab.


Personally, we feel that the chlorine added by most utilities is one of the nastier chemicals routinely found in drinking water. However, it’s easy to remove with a simple taste and odor filter that you can often buy at hardware and discount department stores. These filters contain activated carbon, and they can be placed on the main incoming water supply line (as a whole-house filter) to filter all the water in the house. Unfortunately, some kinds of bacteria can live and multiply in an activated-carbon filter. With public water supplies, most of the harmful bacteria will have been killed by the chlorine, so activated carbon usually works well. But, with private supplies that haven’t been disinfected, activated carbon may not be good idea.


Depending on what your water testing reveals, you may (or may not) opt for a reverse-osmosis filter or a distiller. These are more complex than a simple activated-carbon filter, and they’re usually only practical as under-sink filters to purify water that’s used for drinking and cooking. When you only filter water at one particular location, it’s called a point-of-use filter.


50. What do the different kinds of water filters remove?


There are many companies offering filters today. Big corporations like Sears and Culligan sell them, as well as many mail-order catalogs. We’ve even seen some at K-Mart. There are only a few common strategies, but some models combine more than one filtering method in a single unit.


The simplest filter is a sediment filter. It’s only designed to remove gritty particles and dirt. It can be a good choice if your water is cloudy or muddy looking. (However, make sure the cloudiness is not made up of biological life forms!)


The activated carbon filters mentioned above will not only remove chlorine but also many other dissolved gases and pesticides. Some units have a plastic housing, but others are made of stainless steel. The plastic housings often aren’t a problem for sensitive people because the activated carbon removes plasticky odors and tastes from the water. Some manufacturers use solid, compressed, activated carbon, which is a bit more effective than granular activated carbon. Some filters are large enough that they only need the cartridge changed a few times a year. Others need to be replaced every month or two—depending on water quality and usage. You can also buy small filters that can be fitted onto an individual faucet or shower head.


KDF filters are a fairly recent development. They're able to remove chlorine. In addition, they’re good at removing lead and deactivating hard-water minerals. Another plus is that KDF filters inhibit bacterial growth, so a KDF filter unit rarely becomes contaminated with microorganisms. Whole-house KDF filters and point-of-use models are available.


Reverse osmosis units use a special membrane through which water passes. They can remove dissolved minerals, particulates, and many biological contaminants. Most are point-of-use kitchen models that have a built-in storage tank—which mounts under the sink—and a special faucet at the sink. They require electricity to operate and they waste several gallons of water down the drain for each gallon of filtered water they produce. Their membranes are unable to remove chlorine or dissolved gases.


Water distillers boil water. Solid contaminants are left in the bottom of the boiler unit and the purified steam is separated and cooled (either by room temperature or a cooling device) to produce the filtered water. Water distillers are good at removing particulates and microbes. However, some volatile gases can evaporate with the steam. Distillers produce filtered water slowly, they use electricity, and they require an under-sink storage tank. Most are made of stainless steel, but glass units are also available.


Water quality can be quite a complicated subject, so you may want to have a professional help you select a system—or read up a little more on it. Lynn Bower's book, The Healthy Household, goes into much more depth on contaminants, strategies, and equipment than is possible here.


51. What type of humidifier is healthiest?


A number of people believe having a humidifier is essential for a healthy house—especially in dry climates or where the indoor air in winter gets excessively dry. While this may be true, humidifiers may also cause problems.


If you experience dry or irritated eyes and mucous membranes, the air might be too dry. But, it’s often a combination of dry air and irritation caused by airborne contaminants that's really causing the discomfort.


Air that’s too dry in the winter is usually the result of a house being over-ventilated because it’s too loosely constructed. On the other hand, tight houses in cold climates often have comfortable indoor humidities. If part of the problem is poor indoor air quality, you should first work on the three healthy-house design principles (eliminate, separate, ventilate).


There are two big potential health problems with humidifiers. Most of them are routinely contaminated with mold, bacteria, and a variety of other microorganisms that can become airborne and affect allergic people. Many units also spew irritating minerals into the air that were dissolved in the water (unless distilled water is used in them). While the best solution is to tighten the house so it isn’t over-ventilated, and to improve the indoor air quality, admittedly, using a humidifier is an easier approach.


After considering all the pros and cons of the various humidifier types, we feel there are a couple that are better-than-average. You might look for a steam unit. The high heat will disinfect the water. For whole-house applications, a number of companies make flow-through humidifiers that can be used in forced-air heating systems. The flow-through types have several internal absorbent plates that water runs over. When air blows past the plates, moisture is transferred into the airstream. They don’t have a reservoir, so mold growth is minimized, but a certain amount of water is lost down the drain whenever they’re operating.


Whatever type of humidifier you choose, you should clean it regularly, and it’s a good idea to control it with a humidistat so it will turn on and off automatically. In the winter, if you notice moisture condensing on windows, or if mold is starting to grow on walls (cold corners and closets are particularly vulnerable) there's too much moisture in the air. To avoid the various problems associated with humidifiers, you might simply drink more water, use a skin moisturizer, or mist the air with distilled water instead.


52. Can dehumidifiers also be unhealthy?


Air conditioners and dehumidifiers both pull moisture from the air, making it more comfortable and less likely to result in mold growth or, in severe cases, rot. Too much humidity can also cause formaldehyde and other VOCs to outgas faster.


In general, dehumidifiers are less of a problem than humidifiers, but they usually have a container that fills with water that must be emptied and cleaned regularly. When the container is full of water, it can be susceptible to bacterial growth. A good solution is to get a unit that can be hooked up to a floor drain with a piece of tubing. That way, there’s nothing to empty. Actually, most of the time, dehumidifiers solve more problems than they cause.


Dehumidifiers are often used to deal with a mold problem in a basement. When properly constructed, conditioned, and ventilated, a basement should be dry. However, many basements aren’t properly constructed, conditioned, or ventilated—so they’re damp and moldy. If this is the case in your basement, you should first carefully analyze just why it’s so damp, then try to fix any problems. For example, your gutters might be dumping too much rain water next to the house, there may be broken or clogged drainage tiles, or an older basement may have no dampproof coating. The basement may also be too cool (high relative humidity can be more of a problem when the air is cool) or poorly ventilated. If you decide that repairs are too costly, a dehumidifier may be the most cost-effective option. There don’t appear to be any health-related differences between various models, but some have more capacity that others, and some are noisier.


53. Which is healthier for bathtubs and showers—acrylic or fiberglass?


Actually, steel and cast-iron tubs are the most inert because they have a porcelainized finish. But, when a tub is also to have a shower, you need to have some type of waterproof wall covering. Ceramic tile can be inert, but the grout lines often get moldy. So, many mold-sensitive people opt for a one-piece tub/shower combination because there are no seams for mold to grow. Both acrylic and fiberglass models are fabricated of synthetic materials, but the fiberglass models seem to be slightly less bothersome. We usually recommend that they be purchased early and be allowed to air out before installing them.


The frames around shower doors are notorious for getting moldy. A good solution is to use what are called frameless shower doors. They have an aluminum frame that mounts to the shower walls, but the glass doors themselves have no framing. Instead, the glass has easy-to-keep-clean polished edges. Most also have a free-draining lower track that’s also easy to clean.


54. Is there a healthy bathtub caulking?


For general purpose caulking in bathrooms (and also in kitchens), we like Dap Kwik-Seal Tub and Tile Caulk. It’s widely available in hardware stores, building-supply centers, and lumberyards. It contains a mild fungicide—which is important in damp areas—but seems to outgas fairly quickly. In fact, we’ve found that most sensitive people tolerate it within 4-5 days of application.


(Note: This article is part of the original HHI Archives, and was believed to be accurate at the time of writing. The views expressed in this article are those of the author, and do not necessarily represent those of The Healthy House Institute, LLC.)


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Healthy Home Basics - Plumbing and Moisture:  Created on February 3rd, 2008.  Last Modified on February 28th, 2011


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