Hot-cold water crossover is a legitimate problem in many households.
It can cause the water temperature to go out of sync leading to significant frustration. You won’t be able to use the water as you want to and that can ruin your quality of life.
To fix this problem quickly, you have to figure out what is causing the hot water to backflow into cold water.
Hot water can backflow into cold water due to a misaligned shutoff valve, damaged check valve, high water pressure, or high temperature. It’s recommended to install an expansion valve and cartridge to fix the problem.
The one thing you don’t want to do is leave the problem as-is.
The situation is going to get worse and the water will become difficult to use due to the hot water entering into the cold water. Your goal should be to test each component of the plumbing to see where the problem is.
This article will look at what to do with hot water backflowing into cold water.
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Causes Of Hot Water Backflow Into Cold
1. High Water Pressure
Before finding a hot water backflow preventer, it’s important to consider what is causing the issue. A common reason tends to be high water pressure.
When the water pressure increases, this can cause the water to backflow in the plumbing fixtures. It’s essential to reduce the water pressure if you want to correct the problem.
A traditional plumbing setup cannot tolerate high water pressure because it is designed to work in a certain manner. You will have to account for this to make sure the hot water doesn’t keep backflowing into the cold water.
Fix the water pressure and make sure you are careful about what you are doing.
You can consult with a plumber to work on the water pressure.

2. Misaligned Shutoff Valve
You will want to consider the shutoff valve to see whether or not that’s the problem.
The shutoff valve can become misaligned depending on how it was installed. Even a little bit of misalignment is enough to do quite a bit of damage.
You will want to make sure the shutoff valve is removed and installed again. This will help with the alignment and ensure the shutoff valve works when it is required to.
As you can imagine, when the shutoff valve is not functioning correctly, the hot water will backflow without hindrance.
3. Damaged Check Valve
If there is no cold water from all faucets then it might be the check valve.
The check valve is a critical part of the plumbing and can often be ignored during the inspection phase. You will want to zone in on this part of the fixture to make sure it works as intended.
If not, then this is likely the troublemaker in the plumbing.
The check valve can get damaged with age and you will have to repair or replace it. A plumber will have the capacity to go in and change the check valve.
This is key if there’s hot water when turning on cold.

4. High Temperatures
The temperature can also play a role.
If the temperature of the hot water is excessive, it will start to become a problem. You will want to check how the water is being heated and ensure the temperature is reduced.
This is a must to ensure the backflowing hot water isn’t become impossible to manage. A good plumber can assist with the inspection to see what the main cause is.
How To Fix Hot Water Backflowing Into Cold
1. Replace The Cartridge
The first step is to look at the fixture.
You will want to assess where the problem is and see whether or not the cartridge is the root cause. A cartridge can go bad and this will cause the water to backflow.
You will want to change the cartridge and then check the faucet.
2. Test The Check Valve
The check valve is a renowned troublemaker when it comes to hot water backflowing into cold water.
Your goal should be to test the check valve and make sure you are assessing each step in the plumbing. This is the only way to ensure the check valve doesn’t become the reason for hot water backflowing into cold water.

3. Install an Expansion Tank
Installing an expansion tank is a good idea.
The reason has to do with regulating how the water is traveling and ensuring it goes in the direction you want it to.
It also offers more control in the plumbing, which is always the case with a traditional check valve. Set up the expansion tank for good results.
It should help with the problem and is a good addition even when the problem goes away.
Final Thoughts
These are the tips to consider if hot water backflows into cold water.
Whether it is changing the damaged check valve or fixing the water pressure, it’s recommended to test why the hot water is backflowing into cold water. The best solution is often to install a new expansion tank or replace the cartridge.
These are the best options available for those dealing with hot water all the time.
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