Plumbing System Repair

A home’s plumbing system provides hot and cold water for bathtubs, showers, toilets, washers, etc and then drains it away. This Fix-It Guide on plumbing system repair tells how a plumbing system works, what often goes wrong, how to identify a plumbing system problem, and what parts and tools you will need to fix it. It then directs you to specific fix-it guides for simple step-by-step instructions for pipe repair, faucet repair, and drain repair.

How Does a Plumbing System Work?

Plumbing System Repair

Components of a typical residential plumbing system.

A household plumbing system is the series of pipes, faucets, drains, and their attached devices and fixtures that bring fresh water into a home and take waste water out to a sewer or septic system. Whether the water comes from a municipal system or a private well, water comes into your home through a large pipe. If you purchase your water, a meter on the pipe records your usage. Near the meter is a shutoff valve for turning the water supply off before it enters the house.

When the water comes into your home, one pipe branches off to the water heater to supply hot water to various fixtures. The rest of the (cold) water continues on to the fixtures and appliances. Water in those supply lines is under pressure (about 50 pounds per square inch (psi) so that it will flow rapidly when you open a faucet or turn on a dishwasher or clothes washer.

Other, larger pipes and related drains collect waste water from those same fixtures and appliances and conduct it to a main sewer or septic system.


Make sure you know where the shutoff valve is so you can minimize water damage in an emergency.

What Can Go Wrong with a Plumbing System?

Pipes can leak or break. Fixtures and appliances can also leak. Drains sometimes don’t drain or drain slowly. Fixtures and pipes also get clogged.

How Can I Identify a Plumbing System Problem?

Most plumbing problems occur at a fixture or inside a pipe. The overall plumbing system, the pipes and fittings, seldom cause problems.

  • If a pipe leaks or breaks, turn off the water supply to that pipe or to the entire house, then repair the pipe .
  • If a faucet or appliance leaks, shut off the water supply to it, then repair it (see the Fix-It Guide for faucet or for the specific appliance).
  • If a drain won’t drain or drains slowly, see the Drain System Fix-It Guide.
  • If a fixture or pipe gets clogged, see the Fix-It Guide for the specific fixture or appliance.

Fix-It Tip

Plumbing repairs may get messy, but most are fairly simple. Plumbing relies on just two basic principles: pressure and gravity. The pressure is created by the difference in height of the nearest water storage tower and the elevation where the water comes out of the system in your home. Gravity makes drains work.

What Do I Need for Plumbing System Repair?

Replacement parts are available from local plumbing and hardware stores and home centers. Refer to specific Fix-It Guides for tool recommendations.