Should I worry?

I'm no expert but had one pipe burst years ago that was in an unheated space. It apparently takes repeated freezing and thawing before the pipe bursts after stretching beyond its breaking point. Density of water is lowest at the freezing point.

I'd say, since that is happening with you it would be a good idea to get freeze protection before it happens.

Our pipe burst in the ceiling over the basement family room and caused minimum damage as someone was home at the time. It could have been a real mess. Insurance paid for water damage but not plumbing repair. Plumber rerouted pipe to a heated area.

Dripping does not prevent it from freezing, running does. But that can waste quite a bit of water.

You might want to consider a thermostatically controled wire wrap... which on morns below freezing the heating element keep the pipe warm.

Goog grief! Ask your neighbors. What kind of pipes? PVC will break with little ice pressure. Metal takes a lot more.

Paul

Any exposed pipe should be wrapped with heat tape and insulation. If it's in the wall of heated space, you're probably alright.

Why would it be expensive to insulate them? You would only need to insulate whatever part is above ground. Stuff I would think plenty good enough for AZ is a little over a buck a foot.

So you're living in the house and it has heat, right?

So it's only the exposed pipes that need something? I think that grey split foam tubing would be enough too, since it doesn't get that cold and only for a couple hours, but I add that I used that stuff in my house and it definitely doesn't work hours and hours. I had the hope that the warm water would come out warm at the sink farthest from the water heater. I could only insulate the copper pipe in the basement. The part going from the basement ceiling up the wall to the bathroom on the second floor is still bare. After a while, the water is cold again (and I have to wait until hot water comes all the way from the water heater.) It might take 2 hours, maybe less.

How old is the house btw. Have any pipes ever burst before? What do your neighbors do, esp. the ones with similar houses.

I hate to say yes, in case the answer is no.

That's one hell of a long pipe run! (just funnin' ya!)

Yeah, LOL. I noticed that too when I read what I wrote.

I've been up since 4:30 and I'm still waiting for hot water.

Exactly how much it takes to freeze a pipe is a question most of us have worried about one time or another. There isn't any easy answer. Any we sure don't have enough info from the OP to try to make a guess. But given that the OP said this:

" In the past, with rare long-ago exceptions, the coldest it gets is 28 or so, possibly 25 F."

"Yes, I know about leaving the water drip but that doesn't always seem to work - I've still had them blocked by ice early in the morning. Then too, there's the well pump, water tank and associated plumbing"

All it takes is one rare exception.

The next issue is how exposed it is. Sitting out in the wide open, with free air flow on all sides is going to be worst case. If it's under a porch, in a crawlspace or otherwise partially protected, it will take colder/longer to make it freeze. Another issue is what the pipe material is. But clearly it has frozen enough to block it, how much more you have to go to burst it, IDK, but I would not be taking the chance.

If this is the well water for the house, I don't understand why it would have been installed so that it can freeze to begin with. How exactly to best protect it IDK because we don't have enough info.

If someone is going to be there for sure when it could freeze, then leave the water running so the pump will come on about once an hour. With new 50F water coming in, that will keep it from freezing. A drip won't do it. It's obviously not fool proof because it depends on someone being there, remembering, etc.

Of course, it depends on what you setup is, where the pipes and pump are located in relation to heated areas of the building, etc. Heat tape and/or insulation or boxing in the pump and tank area etc. may be all you need.

You haven't had much of a problem so far, except for some ice blocking in the morning every once in a while.

Since it is a well, you don't pay for water, although you do pay to power the pump. Maybe you could just keep an eye on the overnight temps and if it is going to be cold enough, let the water run more than just a drip during the overnight or just run the water briefly a few times during the night.

If you are really ambitious and can upload a few photos, that may help.

Agreed. That's why a thermostatically controlled pipe wrap heater is the best bet. A mechanical thermostat doesn't draw any standby power so the only expense is the initial cost of the heater and the power to run it when it get cold enough to require it.

That's a small price for the peace of mind gained and it doesn't require anyone to remember anything or to be there if there's an unexpected cold snap. Considering what a mess burst pipes can cause, I'd be shopping for those heaters today if I were the OP, especially since he's reported that the pipes have frozen to the point of blocking already.

Heck, why worry? Drain the pipes on cold nights.

YES - You should always worry! There are millions of things to worry about, and I suggest you worry about all of them!

KenK:

I would buy the electrical heating cable, wrap it around your exposed piping and then insulate over the wrapped pipe.

Water is strange. When you cool it, it shrinks all the way down to about 4 degrees Celsius above freezing, or about 39.2 degrees F. Then, upon further cooling, it expands very slightly as it approaches the freezing point of 0 deg. C (32 deg. F) and then expands by a whopping 9 percent as it freezes. However, once frozen, further cooling of the H2O causes the ice to shrink, just as normal solids shrink as they are cooled.

'File:Density of ice and water (en).svg - Wikipedia, the free encyclopedia'

The point here is that the damage caused by freezing water to masonary, plumbing pipes and everything else, occurs at MILD temperatures, not the bitterly cold temperatures you might expect. H2O expansion from 4 deg. Celsius to freezing generally doesn't do any harm because the water can still flow. However, as the water freezes at 0 deg. Celsius is where the masonary and plumbing pipes crack and the potholes in the road get bigger. Below freezing, the ice shrinks as it cools, thereby relieving the stress previously caused by expansion during freezing. So, if you can get past the freezing point without damage, then further cooling will actually relieve the stress in the pipes and masonary as the ice shrinks, not worsten it.

So, Ken, I'd like to be reassuring you that you have nothing to worry about, but I can't do that. Freezing damage occurs at the freezing point, or the mildest temperature that ice can exist, not at the bitterly cold conditions that generally don't occur where you live. And, you run the risk of cracking a pipe both as the water freezes and as the ice warms back up because the ice will be at it's minimum density (or maximum volume) at the freezing point in both cases.