The Truth about Freezing Pipes… An RX for P.E.X.


Here in the Pacific NW, it used to be that weather cold enough to cause the pipes to freeze in our homes and businesses was rare. Now; not so much.

Now, it seems that every winter we are having those strong ‘cold fronts’ that hit us pretty regularly, and when they hit, they hit a bit harder, colder and longer. Without going through a bunch of detailed statistics, if you look closely at the numbers they seem to bear that out.

In addition to stronger and colder spells hitting us in the winters, we have also been hit with a couple of new ‘urban legends’ about ‘new’ piping that will freeze without breaking; the implication being that ‘we don’t have to worry about the pipes freezing so much now; they’ll be okay”. We may have even seen or heard of some situation where indeed, the pipes froze, the water wouldn’t flow for a couple of days, and when it warmed up the pipes thawed out and ‘no leaks’! What’s the deal?

Well it is true that in the last 10 to 15 years a ‘new’ water pipe material has come into the marketplace in North America that has gained a reputation for being somewhat resistant to freezing and it’s called ‘PEX” pipe. PEX is short for ‘cross-linked’ (x) ‘poly-ethylene’ (PE) pipe.

Cross-linked polyethylene (‘PEX’) piping is indeed a great product. In my opinion it’s a big improvement in piping materials over galvanized steel pipe, copper pipe and even PVC pipe for many reasons, not the least of which is that compared to those other piping materials, it is extremely ‘clean’ in regard to how much it will contaminate the water that it’s moving and holding. PEX piping is also somewhat flexible, like a tubing rather than a rigid pipe, and some brands of PEX have a product ‘memory’ that will allow the product to be bent, kinked, or expanded (even by freezing), and then if re-heated the ‘memory’ will restore the original shape.

DNP Galvanized pipeDNP Copper Pipe

Examples of galvanized, copper and PEX pipes

But here is the catch; no PEX pipe can be expanded and shrunk by freezing and thawing time after time after time indefinitely; at some point all PEX piping will lose its ‘elasticity’ and it could fail/break and spring a leak. Different brands will have different tolerances; but none of them will put up with that kind of activity without springing a leak at some point, and it’s foolish (and against all Plumbing Codes) to install PEX piping in a freeze zone, unprotected.

The ‘protection’ needed for PEX pipe is just like all other piping materials. The first and best protection against freezing is to always run the pipes in conditioned spaces that will be kept above freezing, like inside a wall that has a least one side of it in a heated living space. If that’s not practical or possible, then the pipe needs to be insulated and in some cases wrapped with ‘heat-tape’ and then insulated; it depends on the situation.

If ‘heat-tape’ is needed, our company always recommends a commercial grade product that is shielded and encased in a metallic sheath, so that the outer metallic sheath can be grounded properly. That way, if there were ever a short circuit, the breaker would ‘trip’ and the circuit would be opened (shut-off), preventing fires. Many, many fires are started every winter by cheap, un-grounded heat-tape over-heated and/or short circuiting.

DNP Grounded Heat TapeNon-grounded heat tape

Examples of grounded vs non-grounded heat-tape.

Over time, freezing and thawing may cause pipes to leak, even if you have the ‘new’ PEX piping in your home, condo or town-house. Don’t let a sudden cold snap take you and your plumbing by surprise. Be aware of your plumbing’s condition, and take whatever precautions are necessary for your situation…because there is nothing more unforgiving than water.
Bruce Davis Sr.
Licensed Journeyman Plumber
Licensed Electrician, HVAC/R
Electrical Administrator, HVAC/R
Certified WA State C.E.U. Instructor
Bruce Sr is President of Day and Nite Plumbing and Heating, a 60-year old family owned and operated plumbing and heating business in Lynnwood, Washington.

Bruce can be contacted at: Email:

Day and Nite Plumbing and Heating Inc.
16614 13th Ave. W.
Lynnwood, WA 98037


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