# In residential construction why aren't water pipes insulated? **URL:** \ **Category:** Factual Questions\ **Created:** [January 24, 2026, 4:11am UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974 "2026-01-24T04:11:12Z")\ **Posts on this page:** 12\ **Page:** 3
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [January 27, 2026, 12:12am UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/41 "2026-01-27T00:12:47Z")
I doubt anyone was using lead pipes in 1959. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [January 27, 2026, 12:18am UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/42 "2026-01-27T00:18:32Z")
Probably galvanized but regardless the pipes obviously aren’t lead but copper pipes at least were at one time attached with lead based solder. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [January 27, 2026, 12:39am UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/43 "2026-01-27T00:39:01Z")
Yes, the odds are that my solder has some lead in it. And the copper pipe might have been alloyed with a little lead, dunno. The water intake is probably galvanized steel. ---
**Author:** ![vbob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vbob/32/4439_2.png) [@vbob](https://boards.straightdope.com/u/vbob)\ **Post date:** [January 29, 2026, 9:35pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/44 "2026-01-29T21:35:54Z")
> [@puzzlegal](#): > > And the copper pipe might have been alloyed with a little lead Copper tubing for residential water line use is pretty pure copper: generally 99.9% with traces of silver and phosphorus. The brass for fittings and valves, however, had substantial amounts of lead in the alloy - maximum legally permitted reduced to 8% in 1986, and then to 0.25% in 2014 [in the USA]. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [January 29, 2026, 10:25pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/45 "2026-01-29T22:25:49Z")
Most of my pipes (and fittings) date from 1959. ---
**Author:** ![What\_Exit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/what_exit/32/10652_2.png) [@What\_Exit](https://boards.straightdope.com/u/What_Exit)\ **Post date:** [February 11, 2026, 4:14pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/46 "2026-02-11T16:14:10Z")
A post was split to a new topic: [Alcoholic Texas Man Shoots and Kills Daughter, Jury Declines to Indict](https://boards.straightdope.com/t/alcoholic-texas-man-shoots-and-kills-daughter-jury-declines-to-indict/1027583) ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [February 11, 2026, 8:10pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/47 "2026-02-11T20:10:19Z")
When I was in college, we were putting together a darkroom in the basement of an old house that served as a residence. there was an old sink in there. One of the students had a boyfriend who was a plumber; the guy did all the necessary plumbing in return for two feet of very thick drainpipe sticking out of the floor (replaced by copper) - which had to be twenty or thirty pounds of lead. To me, the ideal recirc system would be triggered by something - simplest is the lights/fans to the bathrooms, or kitchen, but I suppose a motion detector switch would work equally well. (This would give the hot water a 10 or 15 second head start before you turn on the tap, which I hope would be enough. Even a number of false alarms is less problem than running it continuously. And throw in a clock timer for good measure if your habits are regular) ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [February 12, 2026, 4:42am UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/48 "2026-02-12T04:42:43Z")
> [@md-2000](#): > > This would give the hot water a 10 or 15 second head start before you turn on the tap, which I hope would be enough. Not nearly enough in our house. Without the recirc running it is multiple minutes from turning on the hot water tap until hot water arrives. > [@md-2000](#): > > the guy did all the necessary plumbing in return for two feet of very thick drainpipe sticking out of the floor (replaced by copper) - which had to be twenty or thirty pounds of lead. Was he setting up a life size game of Clue? ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [February 12, 2026, 1:13pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/49 "2026-02-12T13:13:45Z")
> [@Marvin\_the\_Martian](#): > > Not nearly enough in our house. Without the recirc running it is multiple minutes from turning on the hot water tap until hot water arrives. Not nearly enough in my house, either. I wonder if the new plastic pipes have a lower thermal capacity than my old copper pipes, and heat up faster? ---
**Author:** ![Limmin](https://avatars.discourse-cdn.com/v4/letter/l/f04885/32.png) [@Limmin](https://boards.straightdope.com/u/Limmin)\ **Post date:** [February 12, 2026, 1:40pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/50 "2026-02-12T13:40:28Z")
Relevant knowledge: While some pipe insulation can help a little, too much might actually have a contrary effect, flowing heat out of the pipe more effectively. It boils down to the increase in surface area of the system (pipe + insulation) being large enough to move more heat than if you had less insulation. (Learned in a heat transfer ME class ages ago) ---
**Author:** ![aceplace57](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aceplace57/32/3500_2.png) [@aceplace57](https://boards.straightdope.com/u/aceplace57)\ **Post date:** [February 12, 2026, 1:54pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/51 "2026-02-12T13:54:29Z")
Plumbers will tell you that pipes shouldn’t be in outside walls. It’s a broken pipe waiting to happen. Unfortunately the layout of some kitchens places the sink cabinet along an outside wall. A good plumber will run the pipes inside the cabinet and not in that cold wall. The homeowner should leave the cabinet doors open during cold spells. I had a slop sink installed in my garage and wrapped the pipes in heating tape. They are on a timer to turn on at 6pm and off at 6AM. I unplug the timer around April for the summer. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [February 12, 2026, 2:29pm UTC](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974/52 "2026-02-12T14:29:17Z")
> [@Marvin\_the\_Martian](#): > > Was he setting up a life size game of Clue? He got a substantial amout of money for doing what he though was a freebie job. This was a pipe about 3 incehs diameter and pipe walls almost 1/2” thick. It seemed like overkill for a pipe to me, but that was what they built with in 1900 I guess. Plus, no it couldn’t be, he wasn’t in the kitchen with Col. Plum. [Previous page](https://boards.straightdope.com/t/in-residential-construction-why-arent-water-pipes-insulated/1026974.md?page=2)