Bathroom Plumbing Basics

small rest  room with standing shower and toilet

What plumbing is needed for a bathroom?

There is more to bathroom plumbing than the things you use every day. The sink, shower, tub, and their faucets, and the toilet. A lot is going on behind the walls, under the house, and up in the attic. To know when something isn’t right in the bathroom and How to get bathroom plumbing fixed, it helps to have some understanding about basic bathroom plumbing.  

How do you install bathroom plumbing?

If you know the bathroom plumbing basics and you’re handy with the tools, you don’t need a professional plumber to set up your bathroom plumbing. Not sure where to start? We offer the following eight steps are generalized instructions for installing bathroom plumbing: 

  1.  Establish Where the Fixtures Go: You can set pieces of cardboard or paper where you want the shower, sink, toilet, and tub. This will help you determine what plumbing lines are needed and where they need to be installed. 
  2. Cut the Openings: Mark the outpoints and drill points then carefully cut them out. 
  3. Shut off the Water Off: Turn all water valves off to the bathroom. 
  4. Run the Cold and Hot Water Lines: You will have five water lines to install cold water to toilet and cold and hot water to sink, shower, and tub. You need to install these lines under the flooring and up to the fixture through the walls. Many people today are using PEX pipes for bathroom plumbing. Older homes have copper, newer homes have PVC. We recommend PEX for its flexibility and durability. Once you have the water lines installed, connect them to the main water line.
  5. Install and Attach Drain Lines: The sink drain line should be 1-1/2 inch, the toilet will be a 3” to 4” line, and the tub will need a 2” line. The toilet drain must aim downward to the main drain. 
  6. Install the Toilet: You’ll need to use a wax seal to attach the toilet’s flat rim to the floor over the waste pipe, making sure the slot and bolt slots are lined up on the toile with the water pipes. Once you have the toilet in place, fasten it down to the floor bolts and the washers then attach the tank to the bowl, the water line to the tank, and caulk around the bowl base for security. 
  7. The Sink Install: Place the sink base into position and drill holes where it attaches to the floor, then attach it with bolt and nut. Attach the cold and hot water lines. Now install the faucet, handles, stopper, and the drain to the sink and position the sink on the base, securing with adhesive and tighten the drainpipe.
  8. Install the Tub and Connect the Shower Unit: Determine where the drain should be, then run the line, making sure it is in alignment. Next, secure the drain line with the adhesive to the tub and position the tub.      

What is good bathroom plumbing?

A new bathroom or a bathroom renovation is an easy task. There are costs0, materials, time, and tools involved that you don’t realize until you’ve started the project. It can become complex, but with determination, it can be accomplished. What type of pipe to use are always a big question when it comes to bathroom plumbing. Here is a basic guideline of the choices out there: 

PEX Bathroom Plumbing Pipe

A flexible pipe made from cross-linked polyethylene. They are rodent resistant, freeze resistant. These are becoming the norm in bathroom plumbing. 

Plastic Bathroom Plumbing Pipe

Inexpensive and lightweight, easy to use, plastic pipe is common in most residential bathroom plumbing. PVC is the most common, other plastics are ABS, PE, and CPVC forms.  Your local building codes may prohibit some, make sure before you buy! The ABS or PVC piping is typically for drain-waste-vent while the CPVC pipe with a PW is rated for plumbing fixtures and water supply lines.

Copper Bathroom Plumbing Pipe

For water supply, this is the best piping to use because it come in a flexible or rigid form. If it will be exposed, there are color choices available today. There are three thicknesses, and again local building codes could dictate which one you need: 

  • Type M – inexpensive and thin
  • Type L –  easy to solder and strong
  • Type K – the thickest copper pipe and recommended for underground water lines

The flexible copper bathroom plumbing pipe comes in two different thickness: L and K with the L being used primarily for gas lines.

Galvanized Iron Bathroom Plumbing Pipe

This was used in older homes and while it is strong, it does corrode, requires repairing and replacing. It is hard to cut and most professional plumbers will recommend repiping with another type of plumbing. 

Cast Iron Bathroom Plumbing Pipe

New bathroom plumbing won’t have cast iron piping because of its difficulty in cutting and fitting.  

What does bathroom plumbing look like?

If you’re building a bathroom, the position and shape are yours to design as you see fit. If you’re remodeling an existing bathroom, what you may have pictured in your mind may not be what is going to work. 

Perhaps you have plans for a big jacuzzi bath to be pictured under a window. If the existing drain and water lines won’t accommodate that, you have two choices: Move the drains and pipes, which could cost you a pretty penny, or redesign your plan. Before you buy that dream tub and the fixtures to go with it, you need to discuss the plans with your contractor or plumber first. 

vanity and toilet in restroom

How does bathroom plumbing work?

The bathroom plumbing must handle water delivery into the bathroom and the waste removal going out of the bathroom from various fixtures. It must efficient, leak-free, and organized, which brings us the two bathroom plumbing system: 

  • Water Supply  
  • Drain-Waste-Vent

As the name suggests, the water supply bathroom plumbing delivers cold and hot water to the shower, sinks, toilet, and tub. The incoming water supply originate at the municipal supply through a meter and the comes into the house at the water heater. 

At the water heater, there are two lines where the water separates to cold and hot and goes to the appropriate faucet in the bathroom.  The drain-waste-vent system is where the wastewater from shower, sink, toilet, and tub empties into the municipal sewer or a private septic system. 

At the shower, sinks, toilet, and tub, there are bathroom plumbing vent pipes that lets the exhaust of sewer gases out through the roof. This provides the drains air pressure so the waste can flow out freely.

Can a toilet and shower share the same drain?

They cannot, do not, nor should not share the same drain. The two drains are separate drains and join together after the wastewater has left the house and join the main sewer line, then on to the wastewater treatment plant.

Are kitchen and bathroom pipes connected?

The kitchen plumbing is separate from the bathroom plumbing.  Just like the shower and toilet plumbing eventually, come together after leaving the house and join at the main sewer line, so does the bathroom plumbing and kitchen plumbing. 

Because the bathroom plumbing is used every day, all day by everyone in your household, it is our recommendation to have either a professional plumber do the work or provide consultant services. This isn’t an area that you want to pipe the wrong thing into a pipe and have wastewater backflowing into the tub or worse, the kitchen! This is why it is so important to have an expert plumber on your side. Call Freedom Flow Plumbing and Heating Services today at (570) 903-3199 for your bathroom plumbing installation in Clifton Township and Scranton, PA.