Walk down the plumbing aisle and you will see a wall of white and gray parts. Most of them fall into five families, and once you can name the family you can find the exact part. PVC is the white or cream plastic pipe used for many drains, vents and cold water lines. Gray electrical conduit looks similar but is not for plumbing.
Sizes are given by the nominal diameter, such as 1 1/2 inch for a bathroom sink drain or 3 inch for a toilet drain. The fitting must match the pipe size exactly, and the size is printed on the side of the part.
Which fitting does which job?
This chart covers the fittings you will meet most often in a household drain or vent.
| Fitting | What it does | Typical spot |
|---|---|---|
| Coupling | Joins two pipes end to end | Repairing a cut section of drain |
| Elbow, 45 or 90 degree | Changes direction of the line | Behind a wall or under a slab edge |
| Tee and wye | Adds a branch line | Joining a sink drain into a stack |
| Reducer or bushing | Steps down to a smaller pipe | Connecting a 3 inch line to a 2 inch line |
| Male or female adapter | Joins plastic to threaded metal | Spigot, cleanout plug or water meter side |
| Cap and plug | Seals a pipe end | Closing off a capped line or a cleanout |
Drain fittings come in sweep and short-turn patterns. Use the long sweep version on horizontal drains so waste flows smoothly.
Not sure which fitting your drain needs? Call (855) 575-2890 and a licensed plumber can sort out the parts and the permit.
Call (855) 575-2890Elbows, wyes and why the curve matters
A 90 degree elbow turns a pipe sharply. That works for a vent or a pressurized line, but a drain wants gentler turns so solids keep moving. A 45 degree elbow, or two of them in sequence, gives a smoother path.
A wye is a branch fitting that enters the main line at an angle. A tee enters at a right angle and is a poor choice for a horizontal drain, because waste hits the wall of the tee and slows down. When you see a sanitary tee, it is built with a curved inlet for exactly that reason.
Couplings, repair couplings and slip fixes
A standard coupling has a stop inside it, so each pipe goes in only halfway. A repair or slip coupling has no stop and slides over the pipe so you can replace a cut-out section. You glue one end, then slide the repair coupling back over the gap and glue the other end.
The repair coupling is the fitting that saves a day when a cracked drain is under a floor and you cannot spring the pipe apart. Whatever the coupling, the joint must be fully inserted, cleaned and glued before the cement sets.
Adapters, traps and cleanouts
A male adapter has threads on the outside and a female adapter has threads inside. These let you join PVC to a metal part or a threaded plug. A cleanout is a tee or wye fitted with a threaded plug, giving access to clear the line later. Always put pipe thread tape or sealant on a threaded joint.
A P-trap is the curved fitting under a sink that holds water to block sewer gas. Its slip joints use rubber washers and nuts and need no cement. The trap arm leading to the wall must slope slightly toward the drain.
Cutting and gluing a PVC joint
PVC solvent cement fuses the plastic, so each joint is permanent. Work in a ventilated space and dry-fit everything first.
Basic gluing steps
- Cut the pipe square with a ratchet cutter or fine-tooth saw.
- Deburr the cut edge inside and out with a knife or reaming tool.
- Dry-fit the pipe and fitting, and mark the insertion depth with a pencil.
- Wipe both surfaces with PVC primer and let it flash for a few seconds.
- Brush on cement, push the pipe in with a quarter turn and hold for about 30 seconds.
- Let the joint cure before running water, using the cement label for the time.
Common mistakes that cause leaks
Skipping primer or cement is the first error. The second is mixing pipe types, such as PVC glued to ABS, without a transition coupling. The third is a joint that was not pushed fully home, which weeps slowly behind a wall.
Another mistake is using drain fittings on a pressurized water line. Drain fittings are rated for gravity flow and not for pressure, so a supply line needs fittings rated for it. If you are not sure what the pipe in your wall is, ask a plumber before cutting.
What Los Gatos permit rules mean for PVC repairs
Ask who files the permit and whose name goes on it. An owner can pull a permit for their own work, but a handyman without a license cannot pull one for you. Ask any contractor to show their license number, and you can verify it with the License Check tool on the state licensing board's website.
The state also raised the dollar threshold that requires a contractor license on January 1, 2025. Paid work above that line needs a licensed contractor, so check the current figure before hiring anyone casually.
For slope, the Town's septic conversion checklist cites the 2022 California Plumbing Code and a minimum pipe slope of one quarter inch per foot. Use that as a reference when you plan a run of drain pipe. Permit rules vary by job, so check with the Town building division before changing anything beyond a like-for-like swap.
When to hand the job to a plumber
Replacing a leaking trap or a single coupling is a reasonable owner project. Moving a drain, adding a bathroom, or splicing into a stack usually involves venting, slope and permits. For those jobs, the plumber we send for plumbing installation handles the work and gives a clear price before work starts.
If a home has failing galvanized or polybutylene supply lines, patching with fittings only delays the problem. A repiping project replaces the whole run. Homes around Saratoga and Monte Sereno vary widely in age, so the pipe in your wall may differ from your neighbor's.
PVC fitting questions answered for Los Gatos
A coupling joins two pipes of the same type and size. An adapter changes the connection, such as plastic to threaded metal.
No. Standard PVC is not for hot water, since heat softens it. Hot lines use copper, PEX or CPVC, and a plumber can match the fitting to the pipe.
The Town issues permits to homeowners or licensed contractors, so an owner can pull a permit for their own work. Check with the Town building division on what your repair needs.
A wye enters the main drain at an angle and keeps waste moving. A tee enters at a right angle and is better suited to vents.
Follow the label on the can, since cure time depends on pipe size, temperature and humidity. When in doubt, wait longer before running water.
Same-day appointments are available when schedules allow. Call (855) 575-2890 and describe the fitting and where it leaks.