How to Winterize Garage Plumbing and Fixtures

This post is about how I go about How to Winterize Garage Plumbing and Fixtures.  We will show you how I shut the water off, drain the lines, and add a special antifreeze. This needs to be done every year before the temperature falls into the twenties.  If it is not done, water in the pipes will freeze and burst the pipes or toilet bowl.

How to Winterize Garage Plumbing and Fixtures

How to Winterize Garage Plumbing and Fixtures – Antifreeze in Toilet

The Water Main

Everyone’s system is going to be different and there likely are not many out there like mine with regards to the water main.  My system has all of the valves three feet down in the ground with a manhole cover over them.  If you have a water main in a manhole, don’t go in the manhole.  There can be poison gas in there.  I have a tool that I picked up at Lowes that allows me to close off the valve without reaching in.  The tool is shown below.

How to Winterize Garage Plumbing and Fixtures

How to Winterize Garage Plumbing and Fixtures – Tool

3 Valves

I have a plastic manhole cover that I remove to access the valves.  I have one main valve, one to an outside spigot and one that drains the line.  The process for my system is to shut the main off, which kills the water to the whole system.  Then I open the drain valve which allows the water to escape from all of the pipes.

All Water Out

To help the system drain better, I open the water valves in the sink and also flush the toilet.  This allows water to go into the pipes and lets all of the water in the feed lines to drain completely.

Close Up the Hole

At this point I cover up the manhole for the winter.  I fully secure the cover on with screws just so nothing or no one can fall down in the hole.

Almost Done

That takes care of the water input side.  Now we have to take care of the sewer line side.  The sink has a sewer trap that holds water so sewer smells do not come up through the sink.  The toilet has a similar trap that prevents smells from coming up.  The water in these traps will freeze if left alone, but you don’t want to completely empty them because then you will have sewer smells in your building.

How to Winterize Garage Plumbing and Fixtures – Sewer Trap


RV antifreeze is the best solution that I have come up with.  First I plunge the toilet to get as much water as possible pushed down the drain.  Then, put the antifreeze in the tub of the toilet tank and flush it.  If you put a full gallon or so in and flush it will push all of the water out and ensure your lines don’t freeze.

How to Winterize Garage Plumbing and Fixtures

The Sink

For the sink, just pour a half gallon of antifreeze down the sink.  Some water will dilute it, but it will be ok as long as you use a half gallon.

Garage Plumbing Winterization

Garage Plumbing Winterization

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The Video

Check out the Garage Plumbing Winterization video below.

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