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Image: Cut away of a faucet showing solder on brass pipes.

Brass and Solder

Brass is a copper alloy that contains 5 to 40 percent zinc as the principal alloying element (among other metals, including tin, iron, aluminum, nickel, silicon, and lead). Zinc is added to brass to increase tensile (tension) strength, and lead is added to improve “machineability” and to make castings pressure tight by filling the voids created as the casting cools. Historically, brass used to make household fixtures contained 1.5 to 7.5 percent lead.

Solder is a metallic compound used to seal plumbing joints. Most solders used in the past contained about 50 percent lead.

Brass and Solder in Distribution Systems and Household Plumbing

Homes that have lead solder, or homes that are connected to the water main by a lead service line, are more likely to have higher levels of lead in their water than those that do not. Experts regard this lead-containing solder as one of the major causes of lead contamination of household drinking water in U.S. homes.

The 1986 amendments to the Safe Drinking Water Act banned the use of solders containing more than 0.2 percent lead in public water systems and household plumbing. The use of lead in pipes and brass fixtures was restricted to 8 percent or less under the Safe Drinking Water Act Amendments of 1996. Despite this regulation, lead-containing solder may still exist in many aging distribution systems and household pipes.

Brass and Solder Corrosion Characteristics and Concerns

Brass fixtures and solder act as sources of dissolution corrosion. Dissolution refers to the dissolving of the metals (that make up the alloy) into the solution in contact with the metal. In this way, metals such as lead, copper, chromium, and cadmium can leach from brass fittings into our drinking water.

Brass fixtures (including faucets) act as sources for dezincification corrosion. Dezincification is a specific type of dealloying, or selective, leaching corrosion. This type of corrosion selectively removes zinc from the alloy, leaving behind a porous, copper-rich structure that has little mechanical strength. This weakens the integrity of the pipes and can form blockages.

Regulations

The following regulations are the National Primary Drinking Water Regulations with which all public water utilities are required to comply.

Regulations to reduce human exposure to brass and solder are:

The Safe Drinking Water Act of 1974 – This is the main federal law that ensures the quality of our drinking water. Under this act, EPA sets standards for drinking water quality and oversees the states, localities, and water suppliers who implement those standards.
The Lead Contamination Control Act of 1988 – This act amended the Safe Drinking Water Act by adding new requirements to regulate the safety of drinking water. Specifically, lead-lined drinking water coolers were recalled.
The Lead and Copper Rule of 1991 – This rule minimizes lead and copper levels in drinking water, primarily by reducing water corrosivity. It establishes an action level of 0.015 milligrams per liter (mg/L) for lead and 1.3 mg/L for copper. The action level is the lowest level to which water utilities can reasonably be required to control lead if it occurs in drinking water at their customers’ home taps. (Note: An action level exceedance is not a violation but can trigger other requirements such as monitoring and treatment.)
The Lead and Copper Rule Revisions of 2001 and 2006 – These revisions streamline and reduce monitoring requirements and the reporting burden. In addition, they address implementation problems and issues arising from legal challenges.
The Safe Drinking Water Act Amendment of 1996 – The 1996 amendment requires federal agencies to comply with federal, state, interstate, and local safe drinking water standards.

Technical Contact:

Darren Lytle (513) 569-7432
Michael Schock (513) 569-7412