Which Is Best For Drinking Water Quality?

Some of our customers ask us about the safety of PEX pipes for drinking water and whether copper is better than PEX.

The answer is that there is no correct answer or 100% perfect solution. Both PEX and copper deliver potable water, and both have some drawbacks. Access to quality drinking water is a large issue, even in cities with ‘safe’ drinking water. Some of our learnings are compiled in this blog.


When a homeowner wants to replace their galvanized water lines, the repipe choices are copper pipes or PEX pipes. Copper is usually preferred from a health perspective, but it is more expensive due to the price of copper. Until recently, copper pipes needed to be soldered, and this increased the time spent on their installation, but with new fittings, soldering is no longer required.

Copper can develop pinpoint leaks over time; these are usually due to electrolysis (the interaction with adjoining metals), or corrosion due to the water’s PH and other factors. In addition, copper mining has an extreme environmental impact on the surrounding land and water.


PEX is cross-linked polyethylene pipe, a kind of plastic, deemed safe for drinking water by all U.S. states. This pipe comes in red, blue, or white colors, with red to indicate a hot-water line and blue a cold-water line. White can be used for both. It is flexible and can be curved which reduces the number of fittings needed in a line.

PEX is about half the cost of copper. It cannot be exposed to sunlight or UV rays or it becomes brittle and cracks. Rodents have been known to chew through PEX lines. PEX has been in use for approximately 30 years in the U.S. and its life expectancy is predicted to be decades beyond copper.

Overall Learnings

Both options fail if damaged and both are vulnerable to damage when garden shovels or heavy tools hit the pipes. Neither option uses glue. Lines of PEX and copper can be joined if needed.

For a repipe, the replacement of a home’s original water lines, Raymark Plumbing & Sewer replaces old, galvanized lines with PEX or copper. Over the years, many plumbing shops and we have seen repipes transition from the majority being copper to the majority being PEX.

There are many articles on PEX drinking water quality and the pros and cons of PEX versus copper. This article is a good one in that it addresses several issues including the overall state of our country’s water infrastructure.

A Good Water Filter

In response to drinking water concerns, Raymark Plumbing & Sewer recommends installing a Custom Pure Point of Use water filter, with a dedicated faucet or tap, usually installed in the kitchen. The filter can remove particles down to 0.5 microns and filter out organics that may come from plastic. Custom Pure is a local company located in Shoreline, WA.

Call Raymark Plumbing & Sewer for a repipe estimate for your older Seattle home and to install a Custom Pure Point of Use water filter. (206) 440-9077.

company icon