Plumber’s Putty: When to Use It vs Silicone and Tape
Plumber’s putty is a soft, clay-like sealant that stops water from sneaking between two rigid surfaces, and it is the right choice for sink strainers, faucet bases, and pop-up drains. It is the wrong choice for plastic, porous stone, and any pressurized or threaded joint. Knowing which is which saves you a callback and a stained countertop.
What is plumber’s putty?
Plumber’s putty is a pliable, oil-based compound you knead by hand and press into a joint to block water migration. It never fully hardens, needs no cure time, and does not bond to surfaces. Most versions are petroleum-based, which keeps them flexible for years. Think of it as a reusable gasket you shape on site, not a glue.
Because it stays soft, a putty seal can be taken apart later without cutting or scraping a cured bead. That reworkability is exactly why plumbers reach for it on fixtures that may need service. A tub of Oatey or Hercules putty runs about $2 to $6 and lasts through many jobs if you keep the lid sealed.
Where to use plumber’s putty
Use plumber’s putty where two smooth, rigid, non-porous parts clamp together under a nut or fastener and the joint is not pressurized. The classic uses are metal sink basket strainers, faucet bases on a metal or porcelain deck, pop-up drain flanges in a bathroom basin, and shower or bath drain bodies seated on a solid base.
- Sink basket strainers on stainless or porcelain sinks, sealed under the locknut.
- Pop-up drains where the flange meets a porcelain or metal basin.
- Faucet bases on a metal or ceramic deck, when no rubber gasket is supplied.
- Bath waste and overflow fittings against a steel or cast-iron tub.
These are the joints you meet on a sink swap. If you are setting a sink strainer during a sink install, putty under the flange is the standard seal. Keep a tub in your basic plumbing tool kit alongside thread tape so you always have the right sealant on hand.
Where you should not use plumber’s putty
Do not use plumber’s putty on plastic, porous stone, threaded or pressurized joints, toilet bases, or outdoors. Petroleum oil degrades ABS and acrylic, standard putty stains granite and marble, and water pressure blows soft putty out of threads. Using it in the wrong place is the fastest route to a leak or a permanent stain.
- Plastic fixtures (ABS, acrylic, PVC): the oil degrades plastic and makes it brittle. Use silicone.
- Porous stone (granite, marble, quartz): oil-based putty leaves a dark stain. Use a stain-free putty or silicone.
- Threaded or pressurized fittings: pressure pushes putty out. Use PTFE tape or pipe dope.
- Toilet to floor: that is a wax ring or waxless gasket job, not a putty job.
- Outdoors or high heat: putty lacks UV and weather resistance and can dry out near hot lines.
For stone or plastic where you still want a putty-style seal, buy the non-staining, oil-free version, sold as Oatey Stain-Free or Hercules Sta Put Ultra. It will not stain porous surfaces and is safe on most plastics.
Putty, silicone, or thread tape: which sealant for which joint?
The quickest way to avoid a mistake is to match the joint to the sealant before you open anything. Plumber’s putty handles clamped, non-porous, non-pressurized joints. Silicone handles plastic, stone, wet seams, and outdoor work. Thread tape and pipe dope handle screwed, pressurized connections. Use this table as your decision map.
| Application | Best sealant | Why |
|---|---|---|
| Metal sink basket strainer | Plumber’s putty | Clamped, non-porous joint that may need service later |
| Pop-up drain in porcelain basin | Plumber’s putty | Compression seal, no pressure, easy to rework |
| Faucet base with no gasket | Plumber’s putty | Seals the deck; use the gasket if the faucet ships with one |
| Drain on granite or marble vanity | Stain-free putty or silicone | Oil-based putty stains porous stone |
| Plastic (ABS/acrylic) drain or shower pan | 100% silicone | Putty oil degrades plastic over time |
| Threaded supply or pressure fitting | PTFE thread tape or pipe dope | Pressure pushes putty out of threads |
| Toilet to floor flange | Wax ring or waxless gasket | Putty has no adhesion and dries out in open air |
| Outdoor spigot or UV-exposed seam | Silicone caulk | Putty has no UV or weather resistance |
Putty and silicone often get treated as interchangeable, but they behave differently once installed. The comparison below shows why you pick one over the other.
| Property | Plumber’s putty | Silicone caulk |
|---|---|---|
| Form | Soft, hand-rolled rope | Gun or tube bead |
| Cure time | None, use immediately | 24 to 72 hours |
| Waterproof | Water-resistant only | Fully waterproof once cured |
| Adhesive | No, it seals by compression | Yes, it bonds surfaces |
| Reworkable | Yes, disassembles cleanly | No, must be cut and scraped |
| Safe on plastic | No (standard version) | Yes |
| Safe on stone | Only the stain-free version | Yes |
| Pressure-rated | No | No (not for threaded joints) |
| Typical cost | $2 to $6 per tub | $8 to $20 per tube |
Neither one seals pipe threads. For screwed metal connections on supply lines, reach for PTFE thread seal tape instead, which fills and lubricates the threads so they seat leak-free under pressure.
How to apply plumber’s putty
Applying plumber’s putty takes about two minutes: clean the surfaces, roll a rope, ring the flange, set the fixture, and wipe the squeeze-out. The steps below cover a typical sink strainer or pop-up drain. Work on dry, clean surfaces, and check compatibility first if the fixture or countertop is plastic or stone.
- Confirm the surfaces are non-porous and non-plastic, or switch to the stain-free version or silicone.
- Wipe both mating surfaces clean and dry, removing old sealant, oil, and debris.
- Pinch off a golf-ball-sized piece and knead it 30 to 60 seconds until soft and crack-free.
- Roll it into a rope about a quarter to a half inch thick, long enough to circle the flange.
- Press the rope into a continuous ring around the underside of the flange, with no gaps.
- Seat the fixture and tighten the locknut or fastener so a bead of putty squeezes out evenly.
- Wipe away the excess with a rag or putty knife, then run water and check for leaks.
Because putty needs no cure time, you can test the joint immediately. If it seeps, tighten a little more or pull the fixture and repack with a fuller rope. Return clean excess putty to the tub and seal the lid.
Does plumber’s putty harden or need to cure?
Plumber’s putty never cures and is not supposed to harden. It stays flexible inside a compressed joint for years, which is what lets you disassemble a strainer or faucet later without a fight. It hardens only when left exposed to open air over long periods, which is why it belongs in tight, clamped joints, not open gaps or seams.
That reworkability is the whole point. When you service a fixture or tackle fixing a leaky faucet, a putty seal comes apart cleanly, unlike cured silicone that you have to slice and scrape. Sealed in its tub, putty keeps for about two years before it dries out and stops rolling into a smooth rope.
Frequently asked questions
Does plumber’s putty harden?
No. Plumber’s putty stays soft and pliable for years and never fully cures. That is by design, so a clamped joint like a sink strainer stays sealed and can be taken apart later. Oil-based putty can dry out and crack only if left exposed to air over long periods, which is why it belongs in compressed joints, not open gaps.
How long does plumber’s putty take to dry?
There is no dry or cure time. You can run water through a drain or faucet the moment you finish tightening the fixture. This is the main advantage over silicone, which needs 24 to 72 hours to cure before it holds water. If a joint leaks after assembly, tighten it or repack the putty right away.
Can you use plumber’s putty on plastic?
Avoid it on plastic. The petroleum oil in standard putty degrades ABS and acrylic over time, making plastic drain bodies and shower pans brittle and prone to cracking. For plastic fixtures use 100 percent silicone instead. Some pop-up and drain kits ship with a rubber gasket, in which case you need no sealant at all.
Is plumber’s putty waterproof?
It is water-resistant, not waterproof. Putty blocks water from migrating between two rigid surfaces under compression, which suits drains and strainers that see water intermittently. It will not hold back standing water or pressure on its own. For a fully waterproof, bonded seal on seams or wet walls, use silicone caulk rated for the job.
Can plumber’s putty be used instead of silicone?
Only for the right joint. Putty works on non-porous, clamped, non-pressurized connections like metal sink strainers and faucet bases. Use silicone instead on plastic, on porous stone, outdoors, or anywhere you need adhesion or a fully waterproof bond. They are different tools, so match the sealant to the surface and the load rather than defaulting to one.
Can you use plumber’s putty on threaded fittings?
No. Threaded and pressurized connections need PTFE thread tape or pipe dope, not putty. Water or gas pressure pushes soft putty straight out of the threads, causing an immediate leak. Putty seals compression joints where two flat surfaces clamp together, while thread tape fills and lubricates screwed metal threads on supply and pressure lines.
Does plumber’s putty go bad?
Yes, eventually. Sealed in its tub, most plumber’s putty lasts about two years. It goes bad when it dries out, hardens, or crumbles instead of rolling into a smooth rope. Always press the lid on tight after use. If a batch cracks when you knead it and will not form a clean rope, replace it rather than risk a weak seal.
Last reviewed: September 2026.