Just like a blueprint of your home’s structure or electrical schematics, a home plumbing diagram can sometimes be helpful. It’s good to know as much as possible about your house, and particularly about vital systems which are frequently installed out of sight. Information shown on a home plumbing diagram includes designations — such as the size of pipes, whether a given pipe is a supply pipe or a waste pipe (drain pipe) — and is also a pictorial route of all pipes and fixtures these pipes connect to.

A home plumbing diagram is handy under a number of circumstances:

  • If you’re planning any sort of remodeling or other work, a map of typical residential plumbing helps avoid damaging pipes concealed inside walls or in the attic or a crawl space.
  • If evidence of hidden water leakage or other water damage appears, a home plumbing diagram can help locate likely suspects, such as a pipe routed through a wall.
  • If you wish to prevent frozen pipes by adding insulation or reduce heat loss from hot-water pipes, a home plumbing diagram will show you the location of these specific pipes.

Where to Find a Home Plumbing Diagram

  • Ask the builder. If your home is relatively new and the contractor/builder that constructed it is still available, you may be able to get a copy of the “rough-in” plumbing diagram for the house. This typically shows the basic routes of all plumbing, the pipe sizes (often color-coded) and the locations of fixtures.
  • Check the county clerk’s office. Blueprints for all structures, including homes, are usually on file with the county clerk. Caveat: Some counties retain blueprints only for a limited time, and some residential blueprints don’t include a plumbing diagram.
  • Ask a plumber to make one. Residential plumbing is often standardized, and experienced professional plumberscan accurately determine the routing of plumbing, as well as the size of pipes present in the house. Usually a simple diagram will contain enough information for most homeowners’ purposes. 

For more about the uses of a home plumbing diagram, contact the plumbing pros at Mowery Heating, Cooling and Plumbing.