You are here:

Plumbing in the Home/Cold water and heating pipes touching.


Good morning.
I have had a new bathroom installation and am suspicious that the cold water feed for the toilet rests on the hot water pipe out of the furnace that heats the house.
I say this because when you flush the toilet, there is a noise in the radiators (not loud, but reminiscent of water running).
IS this a problem, or is it ok, other than the cold water pipe being heated up a little?
Also, will it cause condensation on the cold pipe and could this be a problem or not?
It is between a boarded ceiling and solid oak floor, so is difficult to access. However, if it is a problem, I will have to take the ceiling down.

Dear Ant,

It's not going to cause problems functionally, but it might possibly lead to condensation issues as you suspect.  There is also the possibility of electrolysis with the metal of one pipe reacting with the other.

If it were me, I would put insulation on both pipes and eliminate the contact between them.

Plumbing in the Home

All Answers

Answers by Expert:

Ask Experts


Thomas Ambler


I am experienced at troubleshooting and solving all types of plumbing problems. Issues related to specific manufacturers fixtures and specifications though are beyond my field of expertise. I have dealt with problems in both rural and urban areas, and with water supply and drainage systems. Plumbing issues can be very obscure... such as odors, stains or occasional seepage. I have even had to chase rats from a customer's sewer line.


I have 25 years experience dealing with plumbing systems (which also includes hot water and steam heating systems). My main expertise is in diagnosing and solving problems. I have worked in construction and installation of new systems but do not regard myself as an expert in that area.

Asbury Park Press, Seattle Times, Denver Post.

I completed high school and one year of college. I served 4 years in the Marine Corps and have education in electronic and electrical troubleshooting and repair. I have attended classes on installing and repair of oil burners, and I have EPA universal certification for air conditioning and refrigeration. I am now enrolled as a full-time student at Everest college to re-train for a new career. Any donations of financial support would be greatly appreciated.

Past/Present Clients
All of Denny's Restaurants in NJ, Several Burger King stores, I have done work at two different homes for Bruce Springsteen. I have also worked for Jim Johnson (of J&J) and his family, Whitney Houston, Steve Forbes and many others.

©2017 All rights reserved.