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Why is Hot Water Coming Out of the Cold Tap?

It’s not uncommon to find hot water coming out of cold tap. A normal homeowner reaction is to wait for the water to get cold, but it doesn’t always behave. If you find warm water coming out of the cold side of your faucet, it may be just a minor issue. It could also signal a larger underlying problem, so it’s important to investigate the issue at once. 

Don’t sit around wondering, “Why is hot water coming out of the cold tap?” Call a professional plumber to address the issue and track down the source of the problem. While you should work with a professional to get the issue properly investigated, here are some reasons to consider.

Reasons Why Hot Water is Coming Out of the Cold Tap

1. Location of Pipes

If you notice hot water coming out of the cold tap, it could be due to how your piping is situated. If your hot and cold-water pipes run parallel to one another up to the sink faucet, they can impact the temperature in the opposite pipe. This means that the hot water may feel colder and the cold water may feel hotter. 

This is a common plumbing issue. Over time, the hot water pipe heats the cold water pipe, warming the water inside. Additionally, if your home’s water heater is too close to your cold-water supply pipes, you can end up with warm water coming out of the cold side of your faucet.

2. High Water Pressure

Having high water pressure can feel great in the shower and when washing dishes, but it can become a problem if the pressure is too high. It can cause problems throughout your home’s entire plumbing system, even causing hot water coming from the cold tap.

3. Faulty Thermostats

A lot of the time when you’re facing temperature issues in your home — including hot water coming from the cold tap — you’re actually facing thermostat issues. It’s possible that the thermostat on your immersion heater is broken and not properly regulating your water temperature. This means that it could be overheating the water, causing it to boil over into the cold water supply.

4. Copper Heating Effect

Copper piping has a lot of advantages, largely due to its durability and longevity, but it’s also highly heat-conductive. This means that heat passes through the material easily. If you have hot water running through your copper pipes, it’s normal for it to eat up the entire fixture, enough so that it warms any cold water coming through next. This isn’t anything to be worried about since the copper will cool down on its own in time. 

5. Water Expansion Tank Valves

If your home has a water expansion tank, this piece of equipment relies on a one-way valve to lower pressure on the water meter. Without an operational valve, the hot water flows into your cold water tap. This is an easy way to result in warm water coming out of the cold side. In this case, the broken valve will likely need to be replaced to resolve the issue and get your cold water cold again.

6. Poor Heat Trap Install

It’s so important that you only ever work with a trusted professional on your home’s plumbing projects, repairs, and installations. A bad installation job will lead to costly breakdowns, leaks, and necessary repairs down the road. Something like a bad heat trap installation can cause your warm and cold water to mess up. 

During your home’s plumbing installation, the heat trap must be placed in the water heating inlet. If not, the hot water can infiltrate the cold water lines. Contact John C. Flood right away if you feel this may be the issue.

7. Faucet Cartridge Issues

Modern sink faucets have a cartridge in them to direct water flow. If your faucet has a faulty or broken cartridge, it could be directing water incorrectly or only drawing from the hot water pipe.

How to Fix Hot Water Coming From Cold Tap

Before you attempt to fix hot water coming out of the cold tap on your own, it’s important to note that your home’s plumbing is an intricate system that’s best left to the professionals. Attempting a DIY plumbing repair without the necessary skills or experience can end up worsening an issue. 

Depending on the source of the problem, there are different solutions to fixing hot water coming from cold tap. Here are 4 simple steps for how to fix how water coming out of the cold tap:

1. Turn Off Water Supply

Before you attempt any kind of plumbing repair, it’s important to shut off the water supply. You need to know what’s going on within the piping and you don’t want to trigger a massive water leak. Turn off the water valve before starting.

 In many cases, you can turn off the water to the whole side of the house with the water temperature issue to be safe. Let the water train out of the tap to get rid of any excess water in the pipes.

2. Check Pipe Temperature

Once there is no water in the pipes, you can place a hand against the piping under the sink to test the temperature. Make sure to touch the cold water supply line to see if it’s hot, cold, warm, or room temperature. The hotter the cold water pipe is, the more serious the issue is. 

It’s most common for the source of the problem to be near the sink, and these are the simplest repairs. However, if the source of the hot water problem isn’t near the sink, you will likely need the help of a professional. 

3. Replace the Faucet Cartridge

Modern faucets all have a cartridge in them to divert water. If your faucet cartridge is damaged, it could be directing your water supply incorrectly. Replace the faucet cartridge by unscrewing the faucet, removing the cartridge, and replacing it with a new one. You should always replace the cartridge with the same size and brand.

4. Test Your Faucet

Replace your faucet and turn the water back on so you can test your water supply. Let the water run for a couple of minutes and see if the cold water is cold or still hot. If the water is still hot coming from the cold tap, then you likely have a more serious issue at hand and should call in a professional to assist you.

Trust Your Plumbing to the Professionals

Dealing with plumbing issues is frustrating and can get overwhelming. John C. Flood strives to make your home’s plumbing upkeep as stress-free as possible. Whether you’re having issues with your plumbing, want an inspection, or would like to schedule regular maintenance, our experienced team can help. Contact John C. Flood to schedule a service for all your plumbing needs.