How Home Plumbing Works (Supply vs. Drain)

Introduction

This article breaks down the two “halves” of a home plumbing system—supply (clean water in) and drain/waste/vent (used water out)—so you can understand what’s normal, what’s not, and what you can safely check before calling a pro.

The supply side: clean water delivered under pressure

Think of supply pipes like a pressurized delivery network.

• Where water comes from: city water main or a private well.

• How it gets into the home: through the main water line and water meter (often near the street) and then through the main shut-off valve.

• How it reaches fixtures: smaller “branch” lines feed sinks, toilets, showers, outdoor hose bibs, and appliances (washer, dishwasher, fridge).

What pressure means for you

Because supply lines are pressurized, problems often show up as:

• Drips or steady leaks

• Sudden spraying leaks

• Low pressure at one fixture (often a clogged aerator or a partially closed shut-off valve)

• Low pressure everywhere (sometimes a main valve issue, pressure regulator issue, or utility-side problem)

The two shut-offs every homeowner should know

1. Main shut-off valve: stops water to the whole house.

2. Fixture shut-offs: small valves under sinks and behind toilets

If a supply-line leak is active and you can’t stop it quickly, turning off the main valve can prevent major damage.

LVJR Service Solutions Inc.

13428 Corpus Christi St.
Houston, Texas 77015

832-830-3318
admin@lvjrservicesolutions.com

Integrated facility management and maintenance for commercial, industrial, and residential properties. One call, every trade.