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Comment by SECProto | Hacker News Reader

Temperature at the well stays consistent, but it can vary at the tap. At a family member's secondary property, tap water will vary from 2 deg in winter up to 15 in summer (because the line between the well and the house is only ~3-4 feet deep, and surface temperature changes a lot). If we were drawing more or less/line was different length/different depth, the variation would change.

(I know all these values from homebrewing, where water temperature plays a big role in how long it takes to cool)

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Very rarely used property you can get temperature swings underground next to these pipes. But in normal domestic or municipal settings the regular water through the pipes is going to equalize temperatures year round to within a fraction of a degree at 3-4 feet underground outside of extremely long runs.

Also of note, ~25feet of one inch pipe holds 1 gallon of water. So there can be quite a bit of lag involved, but water is unlikely to spend that long in these pipes to change temperature. Thus the ground temperature would need to be extremely different to make a significant difference once the temperature equalized.

The various municipalities I've lived in require 5 to 8 feet minimum bury depth for water pipes to avoid freezing. The seasonal property I mentioned earlier being at 3-4 feet depth is likely helped by the fact that snow is not cleared above the run (additional insulation) and it is in one of the milder climate areas where a municipal spec water run would only need 5 feet of bury. It may also have half inch of foam wrap for insulation, I'm not sure.

Agree on the pipe volumes.

That’s likely overly cautious. https://www.hammerpedia.com/frost-line-map/

That said, municipality’s will often be overly cautious and they do need to consider property siting abandoned.

> That’s likely overly cautious

I'm not in the country shown on your map. The area of Canada I'm in would be somewhere roughly around the 90" line on that map. It's between the 2000 and 2500 lines on this map [1] (the seasonal property is around a 1500 contour)

The municipalities pay for the main to be installed. They wouldn't spec it to be 8' (2.4m) deep if it didn't need to be.

edit: the contours in my source are not mm of freezing depth, but degree-days of freezing. However, 2500 DDOF corresponds[2] with 70" of frost penetration, while the 1500 DDOF corresponds with 55". So the required bury depths are slightly but not significantly conservative

[1] https://www.urecon.com/applications/images/canadian_map_lrg....

[2] 1962 source: https://nrc-publications.canada.ca/eng/view/ft/?id=15f6f5eb-...

I agree they need to bury it nearly that depth but while IPC 2018 section 305.4 puts water pipes at least six inches below the frost line many places increase that to 12” for water and or sewer.

I don’t know much about how Canada does things.

Yeah, you really don't want those sewer lines freezing...

I'm very confused at the lash back you're getting. Have you all never seen the pipes freeze? Or worse: burst? They wouldn't do that if they didn't swing in temperature. I'm not convinced of SEC's 2-3x estimated increase but the claim that water temperature delivered to your taps vary in temperature is an objective fact. Of course different areas have different infrastructure and can be more resistant to freezing and rupture, but turn on the cold water in the dead of winter and you'll find it is a lot colder than in summer.

I agree water temperature at the tap can vary quite a bit. My parents place has the water go through an unheated crawl space and they would regularly keep the tap on to avoid the pipes freezing when temperatures got unusually cold. Further many municipalities extract water from rivers which experience significant seasonal variation etc.

My comment was simply in reference to well water which has very consistent temperature and will warm or cool the soil surrounding pipes at any reasonable depth if you are using water regularly.

The original point was that a shower would have to use more energy to heat shower water in winter. Not sure now how any of your comments relate to that - do you agree with it?

The relationship is many people don’t experience that. Aka it’s a you might experience X not a you will experience X.

A poster mentioned failing to get a cold shower in Singapore, but Singapores ground temperatures are much higher than we are used so well water is going to be ~25C year round and tap water can be significantly warmer than that.

People don't experience it because the water heater output is a consistent temperature. There's nothing to experience with increased consumption of electric/gas/heating oil, especially when those concurrently increase for home heating

That assumes the water going into the water heater changes temperatures which as I just said isn’t always the case. Some people take “cold” showers year round and the tap is very consistent.

Trivially people in the tropics don’t have a winter, but well water can similarly have very consistent temperatures independent of seasons.

> I'm not convinced of SEC's 2-3x estimated increase

It's a simple calculation, but very location specific. In my particular case, if the water heater is set to 50C, and tap water is 22C in Summer, it has to impart a ΔT of 28C. If your tap water is 4C in winter, the ΔT is 46C. Not quite double, but close to it. If your water heater is in a poorly conditioned space, then it would lose considerably more heat to the surrounding space when outside temperatures are -15C than when outside temps are 35C. All told, hot water energy usage for my particular situation is between 2x and 3x. Other situations would vary, but still significant.

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