Corrosion On Valve at Sinks and Toilets

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Published: December 20, 2014 Last Updated: November 1, 2019
Corrosion on valve at sink, toilet or water heater

A slow, slow leak: often self-sealing

A slow leak at the valve may create a whitish or greenish looking corrosion at the valve area. These types of leaks usually are so small that they aren’t seen and do not damage the area around them. Often these self-seal themselves over time. If you can, avoid knocking off some of the corrosive build-up, it may then start leaking again. Plumbers often recommend that you just leave it alone until you are ready to replace the valve.

The colors

The greenish color generally is corrosion, the whitish (sometimes a cauliflowerish look) is more related to leaking and the calcium and minerals in the water.

Excess flux used in soldering copper pipe will sometimes turn a greenish color over time. Mostly seen where two pieces of copper pipe are soldered together. If the valve or angle stop has a copper threaded fitting soldered to a copper pipe, this will often have a greenish look, due to the plumber using too much flux when he was soldering the pipe. This is generally nothing to worry about.

If dripping

Tightening the fitting will often stop the dripping. If the valve is old or damaged, then replacing it is usually the best idea. Replacing sink or toilet valves are easy and inexpensive to do.

Corrosion on valves and fittings

It rather common for corrosion to gather on valves under the sink in bathrooms and kitchens, as well as at toilet shut off valves. Another common location is on the water heater shut off valve to the water heater. Overall corrosion is generally considered a maintenance type of item. There are contractors that say that corrosion is a little like getting gray hair as you age.

Excessive corrosion

Should the corrosion become excessive or if there is very slow drip, then it common to replace the valve. Many plumbers will recommend that when you replace a valve under the sink, that you do so with a new quarter turn valve, for they last much longer than some of the other type of valves. At the same time they may recommend the replacement of the flexible water supply lines to the faucets.


When purchasing an older home for investment purposes, many investors will go in and repace all the valves and supply lines under the bathroom, kitchen sinks and toilet shut off valves automatically. They figure that the cost of doing this is much cheaper than latter having a plumber come out on an emergency call; or paying for all the damages that a failed or leaking valve caused to the floor and other things, such as a tenants property.

Water heater noises

Also check your water heater for corrosion and the following noises:

  1. Humming  2. Sizzling or hissing  3. Ticking or tapping sounds  4. Gurgling  5. Popping or cracking sounds

Some of these sounds are normal, however, a few can be serious so it would be wise to do a quick check from time to time. (Read about what these sounds are telling you)

Mold in a house

If leaks -check for mold

When corrosion exist, there may be leaks and evidence of mold. In order for mold to exist, there needs to be moisture and leaks often provides the moisture needed for mold to stat growing. It can develop in as few as 24 to 48 hours.

A few of the warning signs include:


Who to consult? Plumbers and qualified handymen.

Home owners will often do much of their maintenance work themselves. Plumbers and qualified handymen are generally very proficient at replacing valves and plumbing maintenance easily and inexpensively. Re-piping is usually done by plumbers or specialty re-piping companies that only do re-piping.

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We have a greenish color on the copper pipe under the bathroom sink. What should we do?

i have corrision under my bathroom sink under the bowl can i fix that this is a question im asking

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