Plumbers putty is really handy stuff, but there are some times when you shouldn’t use it. In this blog post, we’ll tell you when not to use plumbers putty and the reasons why.

When it comes to fixing leaks, many people think of plumbers putty as the go-to solution, which isn’t always the case.

For instance, the type of leak and the material used may or may not work with plumbers putty. In fact, in some cases, the putty may make the leak worse.

So, let’s explore some of the instances when you should use a different sealant rather than plumbers putty.

When not to use plumbers putty

There are times when you shouldn’t use plumbers putty and need to opt for a different type of sealant. Here are a few cases where you should avoid using the putty:

1. When sealing joints between dissimilar materials

Avoid using plumbers putty when sealing joints between dissimilar materials such as metal and plastic fittings. This is because the putty is not compatible with all materials, and it can cause leaks if used on dissimilar materials.

In these cases, a silicone sealant is a better option.

2. Where waterproof sealing required

When you’re looking for a waterproof seal, you don’t want to use plumbers putty.

This goopy, clay-like material is used to create a watertight seal between pipes and fittings, but it’s not the best option for sealing around fixtures that will be exposed to water.

Instead, use a silicone sealant. This rubberized compound forms a flexible barrier that is resistant to moisture and humidity.

3. When installing sink strainers or showerheads

Plumbers putty is not necessary when installing sink strainers or showerheads and it can actually cause more problems.

These accessories usually have their own seals referred to as rubber gaskets that create a tight seal and will prevent water from leaking out. So you should not substitute them with plumbers putty.

4. Sealing leaks on PVC pipes

If you’re trying to seal a leak in a PVC pipe, don’t use plumbers putty.

While it might seem like it would work, over time the putty will degrade and allow the leak to return. Also, the compounds in the putty tend to damage PVC pipes over time.

Instead, use a product specifically designed for sealing PVC leaks. There are many different products on the market, so choose one that best fits your needs.

See also: Can you leave Drano overnight in the sink drain?

5. Where Plastics are involved

Plumbers putty is a type of sealant that is made from a mixture of clay and oil. These components make it effective at sealing leaky pipes and creating a watertight seal around drain fittings.

However, the same components tend to damage plastic surfaces.

The clay in the putty can cause the plastic to become brittle and crack, while the oil can cause the plastic to become discolored and greasy.

For this reason, it is best not to use plumbers putty for plastics. Instead, use a silicone-based sealant that will not damage plastic surfaces.

6. High-pressure leaks

You shouldn’t use plumbers putty for leaks on high-pressure pressure pipes.

The reason is that the putty is not designed to withstand high pressure, and it can actually fail and make the leak worse.

So if you have a high-pressure leak, it’s best to call a professional plumber to fix it.

7. Sealing large surfaces

While plumbers putty is an effective sealant but doesn’t work very well on large surfaces.

If you want to seal a large surface, you might need to use a lot of plumbers putty, but it may fail to adhere properly.

So avoid using it on large surfaces or for applications where a high degree of waterproofing is required.

See also: Plumbers putty or silicone?

Does plumbers putty need to dry?

There’s no set rule on whether or not you need to let plumbers putty dry.

As long as it’s applied in a thin layer and allowed to adhere to the surfaces it’s meant to seal, it should be just fine.

However, most people seem to recommend letting plumbers putty dry for a few hours before using the sink. That way, you’re less likely to run into any problems down the road.

Does plumbers putty harden?

Plumbers putty does not harden but it does dry out. This means that it remains soft and flexible, which is why it’s used to seal around faucets and drains.

Some people mistakenly think that plumbers putty doesn’t harden because it’s not meant to be a permanent fix, but this isn’t the case.

It will actually dry out over time, but it will never be as solid as other types of caulking or sealant.

See also: What happens when you leave liquid plumber in too long?

Does plumbers putty go bad?

Yes, plumbers’ putty can go bad. Exposure to high temperatures or humidity can cause the putty to deteriorate, so it’s important to keep it away from heaters and bathrooms.

It can dry out and start to crumble or crack or become contaminated with bacteria and start to smell and look discolored.

If the putty turns black and smells bad, it should be discarded and replaced with a new batch.


Well, there are plenty of times when not to use plumbers putty. For example, when attaching PVC pipes, sealing large surfaces and high-pressure leaks, waterproofing, or where plastics are involved.


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But there are plenty of instances when you can use plumbers putty such as when you have a leaky faucet that needs fixing or a sink drain.

If you are not sure whether or not to use plumbers putty, consult your local plumbing professional for advice on the best way to fix your specific issue.