What was the most common lead-free solder alternative historically used in drinking water systems?

The most common lead-free solder alternative historically used in drinking water systems is 95/5 tin-antimony. This particular combination consists of 95% tin and 5% antimony, which provides a suitable replacement for lead-based solders in plumbing applications. Tin-antimony solder has good mechanical strength and corrosion resistance, making it a reliable option for connecting pipes in water systems.

Using lead-free alternatives is crucial in reducing the risk of lead contamination in drinking water. As regulations around lead use in plumbing materials have tightened, 95/5 tin-antimony solder has gained prominence in various applications, including potable water systems, due to its effectiveness and safety.

The other materials listed, such as 50/50 tin-lead, contain lead, which is not suitable for drinking water applications because of the health risks associated with lead exposure. Copper phosphorus is typically used for brazing rather than soldering and is not as commonly used in drinking water systems. Tin-silver can be an excellent choice for some electronic applications but has not been widely adopted historically for plumbing in drinking water systems.