Do Fire Hydrants Freeze? A firefighter answers.


Where I work, there are fire hydrants on every street. In fact, they’re so common most people don’t even notice them. However, one question I have heard time and time again is do fire hydrants freeze in winter? And, if they do how can firefighters get water?

As a general rule, fire hydrants will not freeze because there is no water in the lines until the valve gets opened; these are known as dry barrel hydrants. The hydrant connects to a water line placed underneath the frost line deep in the ground. Conversely wet barrel hydrants have water in them all the time and will generally operate in warm-weather locations.

Interestingly, most fire hydrants are designed to withstand cold weather. When a fire breaks out, the tankers that rely on them to feed a steady water supply must be able to get the hydrants opened and working within seconds. Let’s check into this a little further because we all have a few doubts. 

What prevents fire hydrants from freezing?

Fire hydrants of today have had the weather conditions of the area allowed for when designed and installed.

There are two main types of hydrants used today, and as long as they are placed in the proper locations, they should never freeze. Each of them has its own internal design that prevents them from freezing.

Wet Barrel Fire Hydrants

Wet barrel fire hydrants are designed to work in any location of the world that is warm. That means if the area you live in does not ever freeze, this is the type of hydrant you will have.

These are the ones we used to open to cool off in the hot summers. A twist of the nozzle and water starts coming out the exit line. They are simple designs that are easy to understand.

  • Installed directly into the main water lines
  • Above ground valves
  • Mechanical parts are easy to access (above ground as well)

The wet barrel hydrants are that simple. The water inlet pipes of the hydrant connect directly to the underground main water lines.

Water flows through the inlet up into the body of the hydrant.

A twist of the valve or an accident that breaks the structural integrity, and water will spray out, preferably into a firehouse that has been hooked up to it.

Also, I wrote another article about hydrant water safety. Click here to learn if water from a fire hydrant is safe to drink.

Dry Barrel Fire Hydrant

In many areas around the globe, we go through various seasons with distinct features; snow, frigid temperatures, and wind chills that produce cold environments made for polar bears.

But some of us prefer the cold, so we need a fire hydrant designed to hold up to all weather conditions. That is where the dry barrel fire hydrant comes into play.

  • Installed directly into the main water lines
  • Designed with two valves that work below the freeze lines
  • Mechanical parts underground

The dry barrel fire hydrant does not keep water stored in it at all times. The two underground valves open to allow water in and drain it all back out when no longer needed.

When turned, the open valve will pull water up into the hydrant while closing the drain valve to ensure the water stays where it is required.

Once the open valve is shut, the drain valve opens to allow the water to empty back out.

This is the most common type of fire hydrant in my area. In fact, I don’t think I’ve ever seen a wet barrel hydrant in my area.

If you’re interested, I wrote a comprehensive guide to fire hydrants, click the link to check it out.

Can a hydrant still freeze?

Unfortunately, anything can malfunction. The hydrants in warm weather areas will never freeze unless the world continues to shift, which will need to be swapped out for the dry barrel versions.

These types are designed to work in all weather, but issues can arise.

  • Broken valves that allow water in at all times, which means the hydrant could freeze
  • A broken drain valve that keeps the unused water in the hydrant, allowing it to freeze
  • Freeze lines go deeper into the ground, down to where the water lines are, which can freeze.

So even though the fire hydrants of today are built to withstand cold weather, they can fail just like anything else.

Granted, it does not often happen because they are prepped before the cold winters hit.

How is a fire hydrant prepped for winter?

Winter can come on in a blur, creating a fire hydrant that freezes and breaks all the mechanical parts. This is preventable if the work crews get ahead of the weather.

A plan by the city you live in will always be in place, preventing any issues from occurring because of the winterization process that they have in place.

These crews go to each fire hydrant in the city and pump out any standing water. From there, a gallon of house-grade antifreeze will be poured down the lines.

Since the valve that hooks into the water lines below is closed, the antifreeze will sit in the fire hydrant lines for the winter. 

This winterization is in addition to annual hydrant checks. Every year the fire department (or water department) will check every hydrant in the city to make sure it is in good working condition.

Fire hydrants that freeze are not suitable for the neighborhood because they will not be able to be used if a fire breaks out.

That is why city crews have a set maintenance schedule to check them, test them, and prepare them for the changes in the weather.

I always assumed that the hydrants were self-sustainable and never needed to be taken care of. After completing this research, I better understand how they work, and I sincerely hope you do as well.

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