Plumbing: Water Supply

Most large cities rely on water from lakes or rivers for their water needs. Because water drawn from lakes and rivers doesn’t benefit from the natural filtering that groundwater undergoes, larger communities usually pump water to a central treatment facility where it's treated before being stored in water towers. Small to midsize communities often rely on water -- naturally filtered -- pumped from stable underground aquifers. Often only minimal treatment is required to purify the water.

Water towers or elevated tanks serve two functions. They provide storage, so if a power failure shuts down the pump or the well becomes contaminated, the reserve water continues to meet immediate needs. Towers and tanks also pro vide pressure, so gravity can feed water to all of the surrounding homes and businesses.

Water from private wells is naturally filtered but should be tested once a year for coliform bacteria, nitrates and other impurities. In-home filters can often improve water purity, flavor and clarity.

Large-City Water-Treatment System

A surface water-treatment system has several steps. First, chemicals are mixed with the raw water. These chemicals cause suspended particles to clump together or coagulate, and form larger particles, called floc. During sedimentation, floc, silt and other particles sink to the bottom of the tank where the particles are removed. Next, the water is filtered through gravel, sand and anthracite coal to mimic nature’s purification process. In the final steps, the water is disinfected to kill disease-causing organisms and bacteria, it's softened by removing calcium and magnesium, and fluoride is added to reduce tooth decay.

Small-Town Water System

Smaller municipal systems usually consist of a deep well—often in excess of 700 ft. (210 m) deep—a pump to move the water, a chlorinator for disinfecting the water a fluoride dispenser and a water tower that provides both storage and pressure.

Private-Well System

In a private well, a pressure sensor and gauge, usually located inside the house, send messages to a pump submerged in the well to push more water up into the pressure tank as needed. Since the water is drawn from a deep source, it’s filtered as it works its way down and is less susceptible to surface pollution. However, as the water percolates down, it dissolves calcium, magnesium and other minerals. This “hard” water can create rocklike deposits in pipes, water heaters and plumbing fixtures, reducing both the efficiency and life span of a plumbing sys tem and fixtures. Consequently, many homes with private wells need water softeners to filter out the minerals.

Avoiding Lead Contamination

Your home's plumbing system may contain lead from several sources. Municipal water mains laid before 1960 may have lead-sealed joints. Supply pipes installed before 1930 may contain lead. Until about 1986, the solder used to join copper pipe and fittings contained lead. And many faucets with brass fittings and spouts still contain small amounts of lead. Here are some simple steps to avoid waterborne lead exposure:

• When remodeling, replace old pipes or fittings while they’re accessible.

• Use lead-free solder or solderless pipe like PEX.

• After working on supply pipes, remove faucet aerators and let water run for five minutes to remove dislodged pieces of lead or solder.

• Don’t drink, cook or make baby formula with water from the hot-water faucet if you sus pect lead in the system; hot water dissolves lead more readily than cold.

• Flush water for one minute if it has been sit ting in pipes for more than six hours.

• Have your water tested by a qualified lab.

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Plumbing 101: 25 Repairs and Projects You Really Can Do

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