How to Drain the Plumbing System In Your Home

By Danika | July 26, 2022

How to Drain the Plumbing System In Your Home

learn to drain the pipes in the plumbing system before repairs or upgrade

A plumbing system consists of a series of pipes and fittings that, when assembled, convey one or more fluids from one point to another. The systems include built-in water supply and drainage systems within the building and its grounds, as well as those primarily used outside the building. Drainage is usually achieved by gravity via an underground pipe system. This article will focus on how to drain the plumbing system in your home, as well as how to refill them.

Learn how to drain the plumbing system in your home

Essential components of a plumbing system:

1. The water supply provides the fluid and the pressure to push it into the system.

Plumbing systems are designed according to the geographical area in which they are located and the type of building(s) they serve. For example, a single-family dwelling may have a very simple water supply system. In contrast, a high-rise building usually has a more complex system with multiple water supply sources to various parts of the building and complex drainage arrangements.

2. The water pressure.

In some plumbing systems, the water is pressurized before being used to wash floors and fixtures. The pressure applied to the pipe generally depends on the amount of water used as well as its direction of flow. Water pressure affects the flow rate and “flow resistance” of a pipe system.

3. The fixture.

An exterior faucet, sink, toilet, bathtub, or combination allows water to flow into or out of the plumbing system via pipes connected to it.

Pipes are an integral part of any plumbing system. They are usually made of plastic but may also be made of metal or wood. The pipes are joined together by joining material that seals the joints, usually putty or solder. Several fittings may connect pipes, such as taps and valves, which turn the flow on and off.

plumbing remodel blueprint with pipes drained on top of them

Reasons Why You Might Want To Drain a Plumbing System

  • Making repairs to the system.
  • Fixing problems related to water hammer.
  • When winterizing the system to prevent freezing and bursting pipes.
  • Draining is necessary due to a clog or blockage in the system.
  • When preparing to sell a home, show the potential buyer the plumbing condition.
  • When changing the location of a fixture.
  • When changing the type of fixtures in the system, such as switching from a shower to a tub.
  • When upgrading the system to accommodate a new appliance.
  • To clean the pipes if they have become dirty or clogged.

You can merge the above reasons into four main categories:

  1. Making repairs
  2. Winterizing
  3. Water hammer problems
  4. Upgrading with a remodel

Making Repairs

If you are repairing your plumbing system, it is often necessary to drain the entire system or at least the part of the system you will be working on. This allows you to repair without having water in the way, which could make the repair more difficult or even impossible. It also allows you to inspect the pipes for any damage or leaks that may need to be fixed.


Winter preparation for seasonal vacation homes or cabins includes a process known as winterizing. You will definitely need to know how to drain plumbing systems to remove all water from the pipes, fixtures, and appliances. Without this critical step, standing water in the pipes can freeze, causing them to burst when thawed in the spring. This can cause extensive damage to the home, as well as be very costly to repair.

Water Hammer Problems

A water hammer or a hydraulic shock is a sudden pressure surge or wave that occurs when water in motion is forced to stop or change direction suddenly. This can happen when a valve is shut off too quickly, or a pump shuts off abruptly. 

The sudden stopping or change of direction causes a wave of water pressure that can build up and damage pipes, fixtures, and appliances. Draining the system can help to prevent or fix water hammer problems.


If upgrading your home’s plumbing system, you will need to know how to drain plumbing systems before proceeding. This includes all the water in the pipes and any water in the tanks or reservoirs of the fixtures and appliances. This will allow you to make the necessary changes without worrying about water damage. It will also allow you to properly inspect the system for any leaks or damage that may need to be fixed before using the new plumbing.

Drain your homes plumbing system in 5 Steps

1. Turn off the water supply. 

The first step is to shut off the water supply to the entire house or just the section of the house you will be working on, depending on your needs. If you are unsure where the main water shut-off valve is for your home, it is usually located near the curb, in the basement, or in the crawl space. Once you have located it, turn the valve to the “off” position.

2. Open all of the faucets in the house. 

With the water shut off, open all of the faucets in the house to allow any remaining water in the pipes to drain. Faucets may include:

  • tub and shower faucets
  • sink faucets
  • toilet tank shut-off valves
  • laundry tub spigots
  • hose bibs
  • outside faucets
  • any other type of valve or spigot that is connected to the plumbing system

Start with the faucets at the highest point in the house and work your way down. This will help ensure that all the water is out of the system.

3. Flush the toilets. 

After you have opened all the faucets, flush all the toilets in the house to remove any water that may be left in the tank or bowl. You may need to flush each toilet several times to ensure all the water is gone.

4. Drain any remaining water from the fixtures and appliances. 

If there are any fixtures or appliances that are connected to the plumbing system, such as a washing machine, water heater, or dishwasher, you will need to drain any remaining water from them as well. Consult the owner’s manual for your specific appliance on the best way to do this.

5. Keep all of the faucets open.

When you have finished draining the system, it is important to keep all of the faucets open. This will allow any air in the system to escape and help prevent the formation of any vacuum that could damage the pipes.

commercial plumbing system to fill after draining

How to refill a plumbing system in 4 steps

Refilling the plumbing system is relatively simple and only requires a few steps.

1. Close all of the faucets in the house. 

The first step is to close all of the faucets in your home. This will prevent water from flowing out of the system as you fill it up.

2. Turn on the main shut-off valve. 

As the water begins to flow through the pipes, air will be displaced and may cause some water to come out of the faucets. This is normal and will stop once the air has been completely displaced.

3. Open each faucet in the house, one at a time, until water flows freely from each. 

You may need to wait a few minutes for full water pressure to be restored. Once all of the faucets are running smoothly, your plumbing system has been successfully refilled.

4. Flash the toilets.

After the system has been refilled, it is a good idea to “flash” the toilets. This simply means flushing each toilet several times in a row to fill up the bowl and ensure that there are no air pockets in the line. This will help to prevent any clogs or other problems down the road.

bathroom renovation would require draining the pipes before beginning work


Draining and refilling your plumbing system is a relatively simple task, but it does require some thought and proper planning. You need to make sure that you complete the entire process correctly to prevent any problems from arising down the road. This checklist can help to ensure that you have completed all the steps correctly.
For more information on draining and refilling your home’s plumbing system, consult with one of our veteran plumbers. A certified plumber will be able to provide you with expert advice on how to drain plumbing systems in your home and help you to avoid costly mistakes.

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