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6 Reasons That Your Lukewarm Water Is Coming From Cold Tap!

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Have you ever experienced warm water coming out from a cold tap? Sometimes you turn on your cold water tap, and it’s flowing well, but suddenly there’s a change in the temperature, and it becomes warm.

It could happen anywhere and at any time. There’s no particular place or region where this happens. 

So the question now is, what causes this to happen, and what are the solutions to this problem? 

Lukewarm water comes out from Cold Tap due to several reasons. It could result from high water pressure or pipe vicinity. In addition, recirculating plumbing material could also be the reason for this occurrence. 

Why Is there Lukewarm Water Coming Out Of My Cold Tap? 

6 Reasons That Your Lukewarm Water Is Coming From Cold Tap!

When water is in the pipe, the temperature causes the water to heat up because copper and brass heat the water trapped on the cold side.

This process explains why when using the shower for some time and returning later to turn it on, we realize that the water is warm but later goes back to being cold. 

Again, there could be interference from the hot water pipe on the cold water pipe, especially when they are not insulated. Therefore, the two pipes should be run parallel and far from each other.

However, if the hot water pipe is close to the cold water pipe, there’s a possibility that the heat from the hot water pipe would interfere with the cold water pipe. 

When ventilation ducts get warmed up due to the warm air that passes through them, this could cause the cold water tap to be the same, especially when the pipe makes contact with the ventilation ducts.

It usually happens during the cold weather. When hot water in lines causes copper lines to heat up, a situation may occur where the hot water supply becomes so hot that it heats the faucet.

It also includes the cold water lines around it. However, the water gets back cold after being left for some time. 

Lukewarm water is coming out of your cold tap because your pipes may be laid down in an open space, exposing them to sun rays.

When the sun hits the pipes, they get warmer, affecting the water running through them. It is logical. If the pipes are warm, the water would also get warm. 

How to Fix Lukewarm Water Coming From Cold Tap?

It would help if you didn’t freak out when lukewarm water comes out from the Cold tap because this happens often.

However, one crucial thing to do when you notice this or even before this happens is to insulate your pipes.

You should insulate cold and hot water; they’ll always warm up to the temperature around them. 

To fix the lukewarm water coming from Cold Tap, follow these steps as a guide; 

  • Turn off the water supply; this should be the first thing to do once you notice lukewarm water coming out of the cold tap. It will enable you to think about what to do next and determine what could be wrong with the piping. 
  • Check the warmth of the pipes. You should feel the temperature of the pipes located under the sink. However, it is not always under the sink. Nonetheless, you should locate the pipe to feel the temperature if that’s the case. If the cold water pipe is hot, then it’s severe, and you must call a plumber. 
  • You should check the faucet cartridge; if found faulty, replace it as soon as possible. This action won’t take more than an hour to fix. The faucet cartridge controls water flow. Hence, if it is damaged, it will cause the diversion of the water like hot water mixing with cold.

To remove the cartridge from the faucet, remove the screws to remove the handle. Loosen the screw from the valve stem and loosen the cap.

Remove the old cartridge and replace it with a new one. Screw back the sleeves and fix the handle back. 

  • Your valves might have gotten loose with time. Check them out to see if that’s the case. Tighten them if you find out they’re loose. 
  • Finally, test the faucet to check if you were able to fix the problem. Turn on the cold tap, and if it’s still running lukewarm water even after the above steps, the issue is severe and maybe beyond your reach. At this point, call a professional plumber to fix it. 

Six Reasons Why Lukewarm Water Is Coming Out Of Your Cold Tap?

You will face this issue sometimes as long as you use taps in your home. Many people have experienced this while some haven’t, but you should prepare yourself in case this happens.

The table below shows the reasons why water is coming out of your cold tap;

Reasons Solutions
High Water PressureGet a water pressure Regulator
Nearness of PipesGive a distance between the pipes 
Faulty cartridge in the faucetReplace with a new one depending on the model
Bad heat traps installationMake sure you have your heat traps installed 
Heat transfer for ventilation ductsYour pipes shouldn’t be close to the ventilation ducts in your home
Water expansion tank valvesReplace with a new valve if faulty

#1. High Water Pressure

When water from the tap begins to run with so much pressure, it can cause lukewarm water to come out from the Cold tap.

This case is not just when there’s high water pressure. It can also damage your pipes as the force is too much on them. 

#2. Nearness of Pipes

It is essential to know that when fixing the pipes in your home, cold and hot water pipes shouldn’t be close to each other.

Yes, they should run parallel to each other doesn’t mean they should be too close. Having them close will influence the other as the hot water pipes warm the cold water pipe and vice versa. 

#3. Faulty Cartridge in the Faucet

This fault is the first thing your mind should go to when you experience this.

Since the cartridge in the faucet is responsible for water flow, it simply means if it gets damaged, it will malfunction, leaving the whole tap to bring out warm water or cold water without control. 

#4. Bad Heat Trap Installation

Make sure your heat traps are permanent in the water heating inlet. The reason is to serve as a trap in the water heating inlet, as the name implies.

If this is terrible, hot water from the water heater will out freely and mix with the cold water lines making it warm. 

#5. Heat Transfer for Ventilation Ducts

Usually, the ventilation ducts in your home heat up because of their use.

When your water pipes come in contact with this ventilation pipe, there would be some heat transfer to the cold water pipes, thereby making the water warm. In this case, there should be no cause for alarm. 

#6. Water Expansion Tank Valves

The water expansion tank in our homes (if any) needs a one-way valve. This valve is to lower pressure on the water meter.

However, if this valve is unavailable, don’t be surprised when warm water comes out of the cold water tap. Also, if you have one that isn’t very accurate, you will need to replace it. 


This article discusses the major problems that could cause lukewarm water to come out of the cold tap. In addition, the steps for fixing this issue are available.

When you have a problem like this, the first thing to do is stay calm and figure out possible reasons.

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