Lead is a metal found in natural deposits that is commonly used in household plumbing materials and water service lines. Although most homes have very low levels of lead in their drinking water, some homes have levels greater than the USEPA maximum limit. Since you cannot see, taste or smell lead dissolved in water, testing is the only sure way of knowing if there are harmful amounts in your drinking water.
Lead seldom occurs naturally in water supplies like rivers and lakes. Lead enters drinking water primarily as a result of the corrosion, or wearing away, of materials containing lead in the water distribution system and household plumbing. These materials include lead pipes, lead-based solder, brass and chrome-plated brass.
In 1986, Congress banned the use of solder containing greater than 0.2% lead, and restricted the lead content of faucets, pipes and other plumbing materials to 8.0%. Despite these restrictions, many houses, old and new, still have elevated levels of lead contamination in their water systems.
When water stands several hours in plumbing systems containing lead, the lead may dissolve in the water. This means that the first water drawn from the tap after several hours of inactivity can contain dangerously high levels of lead. Problems are most likely to exist in newer plumbing systems which have not yet built up an inner coating of mineral deposits or in older homes where corrosive water prevents the formation of deposits.
When to Test
When testing your drinking water for lead it is recommended that you do two tests. The first test should be a first morning draw used to evaluate lead leached from local plumbing by standing water. Next, supply lines should be flushed and a 2nd draw taken to evaluate lead coming from remote sources outside of your household plumbing.
How to Treat water Contaminated with Lead
If your testing shows that the lead in your drinking water is coming from pipes or fixtures within your house, and not from an outside source, you may be able to reduce the lead through the following steps:
- Flush your pipes before drinking, and only use cold water for consumption. The more time water has been sitting in your home's pipes, the more lead it may contain. Anytime the water in a particular faucet has not been used for six hours or longer, "flush" your cold-water pipes by running the water until it becomes as cold as it will get. This could take as little as five to thirty seconds if there has been recent heavy water use such as showering or toilet flushing. Otherwise, it could take two minutes or longer.
- Use only water from the cold-water tap for drinking, cooking, and especially for making baby formula. Hot water is likely to contain higher levels of lead.
If a water test indicates that the drinking water coming from your tap contains lead concentrations in excess of 15 ppb after flushing, then you may want to take the following additional measures
- Do a comprehensive water test to determine at least the pH and hardness of the water. Acidic and soft water can be very corrosive to the plumbing, causing lead from fixtures, pipes and solder connections to dissolve in the water. Acid neutralizers can be used to treat water with a low pH, making the water less corrosive and less likely to dissolve lead.
- Treatment devices such as reverse osmosis or distillers can effectively remove lead from your drinking water. These devices are limited in that each unit treats only water that flows from the faucet to which it is connected, and all devices require periodic maintenance and replacement.
- If grounding wires from the electrical system are attached to your pipes, corrosion may be greater. Check with your electrician to determine if your wiring can be grounded elsewhere. DO NOT attempt to change the wiring yourself! Improper grounding can cause electrical shock and fire hazards.
- If you receive water from a public water supply determine if the service line that connects your home to the water main is made of lead. A licensed plumber can inspect the service line, as well as, check to see if your home's plumbing contains lead solder, lead pipes or pipe fittings that contain lead. The public water system that delivers water to your home should also maintain records of the materials located in the distribution system. Public water systems are required to reduce the water lead level to below 15 ppb (0.015 mg/L).