Why is Hot Water Coming Out of Your Cold Faucet?

A sink faucet has either a single directional knob or a pair of knobs to control the mix of hot and cold water. Most of the time, this system works well to get the exact temperature that you need for any given task. But, if you’ve noticed that your getting hot water coming out of your faucet when only the cold water is turned on, then you have a problem. In this article, we will look at some reasons why this might happen and what you can do to fix the problem.

The Pipes Maybe Too Close Together

When hot and cold water pipes are installed together, they are typically installed to run parallel to each plumbing fixture and faucet. This is an efficient way to install the water pipes, but there must be a gap between the pipes. The surface of the hot water pipe will heat up as heated water passes through it. If the gap is too small, the hot water pipe surface will heat up the cold water pipe making the water warmer or even hot. This problem can also occur if the water heater is located too near the cold water pipes and it’s a great idea to get the pipes insulated to maintain their water temperature.

A Faulty Thermostat Issue

The immersion heater in your home has a thermostat to control the water temperature to meet your domestic needs. If this thermostat develops a fault or it breaks down entirely, you can expect to receive a large volume of very hot water. This delivered water is actually superheated, and it will boil over and affect the water delivered to the cold faucets in your home. All of the water stored in your tank will be warm due to the mix of hot and cold water. Contact your local certified plumber; they can fix or replace the thermostat for you and get your water temperatures back to normal.

The Ventilation Ducts

When it’s colder outside the ventilation ducts can feel warm to the touch due to the warmed air that is passing through them. If you have cold water pipes touching the vents somewhere in your plumbing system, the water carried by those pipes will become warmer. During the winter months, this may be very noticeable as the heating system is used more extensively, and it may be set to a higher temperature. Insulating the water pipes will prevent this from occurring by isolating the water pipe from external temperature changes.

Taking Action to Fix the Problem

When you turn on the cold faucet and hot water comes out, it can be a disconcerting experience. But, in extreme cases this water could be very hot, it could even scald an unsuspecting person, and this could result in a trip to the emergency room. As we have shown above this issue can be relatively simple to identify and fix. A local professional certified plumber can restore your water temperature to normal quickly.

By Giovanni Longo President Flood Brothers Plumbing
Giovanni Longo is a 3rd generation master plumber who has been practicing his craft and trade in the greater Los Angeles area for well over a decade and a half. A plumbing and hydraulics-engineering innovator, Giovanni’s particular world-class expertise focuses on dealing with challenging sewer system designs as well as resolving complex commercial and residential draining issues. As a certified Flood Mitigation expert, he is also well versed in a wide variety of water damage and remediation solution.