How do I install or replace a shower drain?

Identify the drain and waterproofing products, not just the floor finish. Oatey's cited no-caulk guide covers a washer-and-locking-ring drain for compatible preformed bases. Its pan-liner guide covers a clamping-ring drain for a conventional liner and mortar bed. These are examples, not the only available systems. A bonded sheet or liquid-membrane system requires its own approved drain connection.

Then ask whether you can reach the underside. The no-caulk drain tightens from below, with a locking ring on the underside of the base. Oatey's instructions attach the drain to the base first and put the base into its final location afterward, which shows the design expects you to reach it from underneath. In many Phoenix homes built on a slab, there is no crawlspace or ceiling below the shower, so that access may not exist without lifting the base. If you cannot reach the underside, that is the point to stop and get a plumber's opinion.

Signs the drain needs work are simple. Oatey lists leaks, slow drainage and visible damage to the drain or the surrounding area. A drain that is only slow may just be clogged, so try the steps for a drain that keeps clogging before you take anything apart.

For the particular Oatey no-caulk system in the cited guide, seal the flange, tighten its locking ring, seat its pipe gasket and install the cover. Oatey says most installations can be completed in under two hours with basic tools. You need adjustable pliers, a screwdriver, plumber's putty and the drain kit. Oatey's guide runs like this:

1. 1Apply a bead of plumber's putty around the underside of the no-caulk barrel flange. For an ABS drain, use silicone.
2. 2Insert the barrel through the top of the base hole and press down firmly without twisting.
3. 3On the underside, place the rubber sealing washer and friction washer over the barrel.
4. 4Tighten the locking ring with adjustable pliers until it is secure.
5. 5Remove any extra putty from the top of the drain.
6. 6Place the rubber pipe gasket, bevel side up, over the drainpipe that comes up through the barrel, and push it down until it sits at the bottom of the barrel.
7. 7Thread the gasket set screw into place with the provided wrench, then tighten it with a screwdriver.
8. 8Snap the drain cover on.

Between the barrel and the gasket, Oatey has you set the base into the prepared shower footprint, level and properly aligned. Its guide also says to double-check all seals and gaskets for a watertight fit and to test the drain for leaks before finishing the shower installation. Run water in the pan and look under it. Oatey is blunt about the fine print: "Always follow the manufacturer’s instructions for your specific drain and base." Brands differ, and the kit's sheet beats any general list.

If you are removing an old drain, expect the old putty or silicone to be firm. Scrape the opening clean and dry before you seat the new flange, so it sits flat against the base. A flange that rocks will leak.

Use the sealant approved by both the drain and base makers; some materials require silicone rather than putty. Oatey's FAQ says to use putty for most drains but silicone for ABS shower drains to avoid damaging the material. That means you need to know what your drain body and base are made of before you open the tube.

The putty formulation and material-compatibility guide separates specific product approvals from a general PVC-or-ABS label; follow the installed drain and base instructions.

The code sets a few basics. The model International Plumbing Code, in section 421.3 of the 2024 edition, requires a shower waste outlet not less than 1 1/2 inches in diameter, with a removable strainer not less than 3 inches across. It also requires an approved connection between the outlet and waste pipe. The approved system decides which connection parts are required. Phoenix adopts its own amended version of the plumbing code, so treat this as the model rule and confirm details with the city.

For a tile shower, the code also covers the floor. Section 421.5.2 says the liner under a shower floor must be pitched one-fourth unit vertical in 12 units horizontal, a 2-percent slope, toward the drain, and securely fastened to the waste outlet. Our page on shower pan liner code goes deeper on that. Prefabricated receptors are the exception, since the base is already a sealed unit.

For a conventional tile-shower pan liner, the drain connection is part of the waterproofing. Other tile systems follow their own listed details. Oatey's pan liner guide shows why. The drain base screws to the subfloor, the liner is draped over the drain base, silicone goes around the inner flange, and the clamping ring is tightened down over the bolts until it has a snug fit against the liner. If the liner is cut, cracked or clamped badly, water gets into the framing.

Oatey also warns not to use felt paper with the pan liner, since the petroleum in it can react with the liner and cause it to crack or become brittle. And the guide ends with a flood test: after the adhesives cure overnight, plug the drain, fill the shower floor to about curb height, and let it sit at least two hours. There are no leaks if the level has not dropped, the area around it is dry and no water shows on the ceiling below.

Replacing a drain in a finished tile shower can require opening tile and mortar and restoring the waterproofing. That is not a Saturday repair. It also ties into a leaking shower valve behind the wall, since a stain on a wall or ceiling could come from more than one source.

Swapping a drain part on a preformed base usually does not need a permit, but changing drain pipe does. Phoenix's adopted 2024 building-code amendment says a plumbing permit is not required for clearing stoppages or repairing leaks in fixtures, as long as no valves, pipes or fixtures are replaced or rearranged. It says that if a concealed trap or drain pipe must be removed and replaced with new material, the work counts as new and needs a permit and inspection. Confirm the scope with Planning & Development before altering the drain or base.

Call a licensed plumber for any tile or stone shower, for a cracked or corroded drain pipe or trap, when the base has to come out, or when you see a stain below an upstairs shower. Those jobs involve the liner, the pipe and code, and a leak inside a wall or slab is hard to trace. HQ Plumbing & Air is licensed and insured, offers 24/7 emergency service, and gives free estimates and upfront pricing.