Solders and flux may not contain more than what percent of lead, as mandated by the Safe Drinking Water Act?

• A. 0.02%
• B. 0.5%
• C. 0.2%
• D. 1%

Answer: (C)

Materials that contact drinking water must be essentially lead-free to reduce health risks. For solders and flux used in plumbing, the limit is very small: lead content may not exceed 0.2 percent by weight. This means, for every 1000 grams of solder or flux, no more than 2 grams can be lead. Keeping lead so low helps prevent lead from leaching into water as pipes and joints age or corrode. Inspectors look for product specs showing compliance with this limit, because exceeding it would mean the material isn’t considered lead-free for potable-water systems. The other options would allow more lead than these protective standards permit, which is why 0.2% is the correct threshold.