ABBEY HOME INSPECTORS, INC

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Technical Letter

LEAD IN DRINKING WATER

Parents Concern

In our last letter on the problems of lead in paint, it was pointed out that even minute amounts of lead in a child’s daily diet can cause serious health problems.   The U. S. EPA estimates that only 10 to 20% of the total lead exposure in children is caused by lead in drinking water.  These statistics may, however, be biased by the severe cases of lead poisoning caused by paint and other sources in poorer neighborhoods.   The U. S. EPA found that infants whose diets consists of liquids made with water, such as baby formula, lead in drinking water makes up an even greater proportion of total lead exposure (40 to 60%) without neighborhood distinction.

St. Louis Children’s Hospital completed autopsies of 64 "Sudden Infant Death Syndrome" infants, and 23 infants who died suddenly from other causes between the ages of 4 to 26 weeks.  The infants with SIDS had 43.9% more lead in their livers and 68.5% more lead in their ribs.

In 1992, under the authority of the Safe Drinking Water Act, the U. S. EPA set the action level for lead in drinking water at 15 parts per billion (ppb).  The previous action level was 50 ppb.  The EPA has also set a Maximum Contaminant Level Goal of zero for lead in drinking water.  This nonenforceable "Goal " is an optimal level at which no adverse health affects are anticipated, and implies, that for parents and pregnant women especially, only the lowest possible lead levels attainable should be satisfactory.

Sources of Lead

The sources of lead in our drinking water is predominantly from corrosion and erosion of the pipes, fittings, and faucets within the house, and of the service pipe line from the street main to the house.  The lakes and wells, which supply water systems, are generally lead free.  The street main pipes are generally iron, transite and other non-lead products but past use of lead joint packings allow for a source of lead problems.

The service line from the street main to the house (see sketch) is often pure lead pipe and can be a prime suspect as a source of contamination.  Until 1987, when it was banned under the Clean Water Act, lead was a popular choice of water utilities for service lines because of some of its engineering properties.  Lead pipes can also be found in the water pipes in older homes.

A very common source of lead in house drinking water is the solder used to join copper piping.  Another common source of lead are the brass faucet and fittings.   Solder for copper piping normally contained about 50% lead before activation in 1988 of an amendment to the Safe Water Act signed by President Reagan.  The amendment reduced the allowable level of lead in solder to 0.2%.  The amendment also limited the amount of lead in pipes and fittings to 8%.

This law does nothing for installations before 1988, and does not provide for adequate policing of plumbers and suppliers to assure compliance with this law.  Some states have indeed found illegally used lead solder in new installations.

Some cities have been systematically replacing lead service lines.  Phoenix, Arizona has replaced nearly all of its lead service lines.  Chicago commonly used lead service lines until the ban, and there was no indication of a removal program.

For homes with wells rather than community supplied water, the EPA issued a warning regarding new brass pumps in April, 1994, via the news wires.  The EPA said tests have shown some water from the new pumps contained lead in amounts well above its danger level.  The California attorney general and two environmental groups have sued four water pump makers.  The pump manufactures in question are Goulds Pump, Aeromotor, Sta-Rite, and F. E. Myers.

Water Quality Factors Affecting Lead Content

Corrosion of the piping system, including the fixture and pumps, is a major factor in lead leaching into the water supply and the water quality itself impacts on corrosion.   Several factors cause water to be corrosible including acidity, high temperature, low total dissolved mineral contents, and high amounts of dissolved oxygen.  Hot water has much higher lead levels than cold and should not be used for cooking.   Boiling water does not remove lead, but will increase concentrations.

Naturally soft water is known to be highly corrosive, but the Water Quality Association argues that soft water from water softeners does not increase the corrosiveness of water.   They argue that naturally soft water has a combination of the previously stated quality factors including acidity which cause the corrosion, and it is not the softness which cause corrosion.  In fact, they argue, if lead is found in water before it reaches the house, a water softener can significantly reduce lead levels.

Scientific data shows that the newer the home the greater the risk of contamination.   It was found that lead levels decrease because mineral deposits form a coating on the inside surface of pipes as time passes.

Because of these positive and negative factors affecting lead levels, many communities use additives to water systems to control lead levels.  New York is conducting studies to find the most effective concentrations of calcium orthophosphate for coating pipes to reduce lead leaching.  Chicago uses additives to eliminate the acidity and increase the ability to coat pipes. Homeowners should contact their community supplier to discuss what control measures are being taken.  Suppliers should, by law, be proactive in providing lead level control measures.

Variations with Draw Time

The amount of lead in a sample will vary substantially from first draw at a faucet to that found after flushing the lines.  In one test in a first floor bathroom the first draw had lead levels of 900 parts per billion while after one minute of running the lead levels were reduced to 64 parts per billion.  Lead will accumulate in the pipes as the water sits.  The longer it sits, the larger the accumulation.  Flushing the lines eliminates this accumulation.

For this reason, it is important to take at least two test samples (1st draw and 1 minute flush) for analysis for a better picture of conditions.  If the first draw sample is higher than 15 ppb in lead levels, you should contact your supplier about the problem, and consider taking some corrective action, including installing a treatment system to remove the lead.

Treatment Systems

There are several effective treatment systems that consumers can install to significantly reduce lead levels at the faucet.  Reverse osmosis, distillation, water softeners, and solid block and precoat adsorption filters, which are made with carbon to activiate alumina, are all effective in reducing lead levels in addition to removing other contaminants.  Commonly used carbon filters for the purpose of removing chlorine and other chemicals are not effective in reducing lead.  Contact the National Sanitation Foundation at (313) 769-8010 or the Water Quality Association at (630) 505-5161 on the effectiveness of filters in removing lead.

Conclusion

The EPA states that lead levels in your drinking water are likely to be highest if :

A. Your home has faucets or fittings made of brass which contain some lead or,

B. Your home or water system has lead pipes or,

C. Your home has copper pipes with lead solder and

             -your home was built before 1988 or,

            -you have naturally soft water or,

            -water often sits in the pipes for several hours.

The best way for a consumer to find out if there is a lead problem in the house is to test the water at a qualified lab.  For real estate sales inspections, Abbey Home Inspectors advises clients to take their own samples for testing to keep inspection costs to a minimum.  The lead issue, whether in paint or water, can be the most important confronting a prospective homeowner.  We feel that it is important to become knowledgeable on this meaningful subject.

Robert V. Gallo P. E.