Plumbing an entire bathroom may seem like a big project and in some cases it is. Running all the waste and water lines through floor joists and walls can take some planning and trial and error.

That's the hard part of plumbing a bathroom and it's different for each project. Take some extra time to draw out your plans to make sure you'll be running lines the best way possible.

Once you've run the waste and water lines, the rest of the job involves getting all the fixtures in place and hooking them up.

Setting Toilets

Most toilets are assembled in two pieces: a bowl and a tank. Setting both pieces as one unit can be awkward and heavy. If possible, install the bowl first, then the tank.

The fitting that connects the toilet to the waste pipe is the closet flange. In new construction, this piece is probably already roughed-in.

To install a closet flange, dry fit it into the waste pipe so it sets level on the floor. Glue it into place so the slots will line up with the toilet bolt holes.

NOTE: The closet flange may be plugged with a rag. Or the flange may have a plastic "seal" in its center. It's made that way to block sewer gases until the toilet is set. Knock out the piece or remove the rag when you're ready to set the toilet.

Position the closet bolts in their slots. Turn the toilet upside down and fit a wax ring gasket onto the toilet's outlet (horn).
Set the toilet over the bolts and onto the flange. An easy way to seat the ring is to literally sit on the toilet and rock it a bit.

Then put a level on the rim of the bowl and shim the base if needed. Snug, but don't overtighten, the nuts and washers onto the closet bolts and again check the bowl for level.

Attach the tank bolts/nuts to the bowl (with the nuts outside so they don't rust). Hook up the water line, fill the tank, and adjust the float as needed. Finally, caulk around the base.

Installing Pedestal Sinks

A pedestal sink can provide "openess" to a bathroom -- even a small one. It doesn't provide any storage or counter surface like a vanity, but uses less floor space. And they look nice, too.

Consider using white PVC pipe (not black ABS) if you're installing a light-colored sink. It will likely blend better although that area of the sink is hardly seen.

A pedestal sink is usually a two-piece unit: a stand (base) and a sink. The sink mounts to a bracket on the wall and also sets on the stand.

Let's assume the water supply lines, shut-off valves, and drain pipe are roughed-in. Mount the wall bracket for the sink and check that it's level.

Position the stand and test fit the sink on both the bracket and stand, adjusting the stand if necessary.

Remove the sink and mark where the floor bolt goes that fastens to the stand. Drill a hole and fasten the bolt with a nut under the sublfoor or mortar it in, then secure the stand.

Connect the sink's water valves, handles, supply lines, stopper, and drain piece. Set the sink on the bracket and stand. Glue an adaptor coupling with threads to the drain stub pipe.

Fit the plastic trap piece to the sink drain and adapter. If needed, add a short piece of PVC pipe to extend through the adapter. Finally, tighten the trap's compression nuts to the adapter and drain threads.

Installing Vanity Sinks

Installing a vanity cabinet and sink is an excellent way to get more storage and countertop space out of your bathroom.

Keep in mind your storage needs, size requirements/limitations, and personal tastes when selecting a vanity.

The roughed-in stub may already have a threaded adapter glued on and the line should be plugged with a rag to stop sewer gases.

The water lines should have caps soldered or glued and you'll need to cut them off once the vanity is set.

Measure the water and drain line locations on the wall. Transpose them to the back of the vanity and cut holes out for them.

Cut the vanity's sink opening if it isn't already. Set the vanity over the lines and against the wall. Check that the cabinet is setting level/square and secure it in place.

Connecting Vanity Sink

Following manufacturer instructions, connect the spout, water valves and handles to the sink. Link the supply tee and hose assembly to the spout.

Our sink had braided steel lines that we looped to the valves and fastened them with coupling nuts.

Attach the water supply lines to the valves if possible, to avoid reaching up under the sink later.

Apply plumber's putty around the drain fitting to form a seal and seat the fitting in the drain hole. Add a washer and slip nut on the bottom and tighten the fitting.

Screw on the drain stopper coupling and its gasket so it lines up with the back of the sink. Feed the stopper's slip arm through the faucet and connect it to the stopper coupling. Push the stopper fully open and tighten the arm down.

Flip the sink upright and set it in the cabinet. Remove any rag or cap plugging the drain stub. Glue a threaded adapter coupling onto the drain stub. Fit the trap and screw it to the adapter and sink drain.

Tighten the sink water lines to their shut-off valves. Slowly open a shut-off, check for leaks, then check the other line.

Fill the sink, check for leaks around the drain, then drain the water and check the waste line joints. This will also put water in the trap to stop sewer gases.

Caulk around the rim of the sink to seal out water and to finish off the sink installation.

Hooking Up A Tub/Shower

A combination tub/shower unit is an affordable, practical way to save bathroom space.

The following section describes the basics of plumbing in a tub & shower unit, but free-standing bathtubs are plumbed the same way.

CAUTION: A filled tub can put a lot of weight on floor joists and additional bracing may be needed. Also, a new tub may not fit through some doors.

Measure and mark the tub outline on the floor to estimate where the drain will be. A tub unit may already have its drain and overflow drain installed. Otherwise, connect them before setting the tub.

If possible, lay out the drain pipe to run with joists, instead of across them. If not, you'll have to notch or drill holes in the joists for proper flow. You may also need to double the notched joists to strengthen the floor.

Run a drain line to the soil stack. Dry fit, then glue a tee in the waste line to connect the tub drain and overflow. Add a trap below the tee and try to locate it between joists to avoid notching.

"Dry fit" the tub and double-check that the drain connections will line up. Set the tub and check that it's level.

Shim between the tub and support boards if necessary. Nail the tub flange to the supports, secure it in place and connect the drains to the tee.

Connecting Tub & Shower Water Lines

Measure the distance across the tub riser's hot and cold inlet fittings. Check that the incoming water lines are that same distance apart as the riser fittings.

Shut off the water supply, cut off the water line caps and solder the riser to the water lines.

Nail a support block about 6' off the floor between two wall studs and secure the riser to it. Set the tub so the riser fittings extend through their holes.

Check the tub for level and secure it in place. Wrap Teflon® tape (clockwise) on the riser threads (unless instructions say otherwise).

Screw on the valves with an adjustable wrench and put on the knobs. Hand-tighten the faucet and shower head. Then tighten them a bit more with a belt-like tool called a strap wrench.