How to Make Your Own P Trap Drain Pipe from PVC Fittings

Take a look under your kitchen/bathroom sink. If your p trap is original the house (in my case, from 1960s), it probably needs to be replaced. Yes, you may see a brass or chrome fitting(s) that look sturdy ad in good shape but what I found out was that looks can be deceiving.

P-TRAP KITS

There are multitude of available options such as the a la carte of piecing everything together, brushed bronze, chrome, brass, ABS, PVC, plastic, etc, etc. There is so much, it can actually give you a headache, trying to figure out what is needed for your p-trap replacement project.

Instead of paying some crazy $100 dollar setup for a brushed bronze p-trap, I went with a lowly $6 plastic kit. What I did not like about this setup was the use of multiple slip joint connections (which can be leak prone), as well as the thin, translucent plastic material which looked pretty flimsy (I actively use the storage space under the kitchen sink, storing dog food and dog toys, so I wanted the p-trap to be sturdy against bumps and remain leak-proof).

GATHERING PVC COMPONENTS

I wanted the ability to full disassemble the connections (All components are for 2″ PVC schedule 40, except for the tail piece)

Tail Piece – db HP 9803, SKU 041193057310 MIP fitting – C4801-2-7, SKU 039923-214287 Trap – C4895, 039923-225467 FIP fitting – c4803, SKU 039923-213549 1.5″ Flange washer – Dearborn Brass, HD7195C, SKU 041193-038654 1.5″ Slip Joint Nut and Washer – Dearborn Brass, HD2698C, SKU 041193-01530-3 1.5″, 4 ft PVC pipe Oatey Purple Primer and cement

REMOVING OLD P-TRAP

When I first detected a sign of water leakage under my bathroom sink (warped or bubbled wood surface inside the cabinet), I figure I would just replace it with one of those $5 p-trap kits and spend about 15 minutes.

15 minutes turned into 1 hour when every single component of the drain (tail pipe, slip joint, p-trap, etc.) all disintegrated in my hands.

After using my hacksaw, chisel, hammer, pliers, channel locks and plenty of choice words, I was finally able to get started on installing my new p-trap.

Your job will go considerably faster and easier if your current setup is plastic or ABS. Otherwise, budget some extra time bring plenty of patience!

ACCORDION STYLE DRAIN?

At first, I found this nifty accordion style drain (Dearborn Brass, 1 1/2″ coupling, SKU 04119314788) from one of the large box retailers and installed it in my mudroom. Well, to make the long story short, just because it is available for sale does not mean it is code approved for your location.

Before buying and installing this type of pipe, make sure to call ahead and ask to save yourself a headache!

STEP-BY-STEP GUIDE

STEP 1 – For a PVC male fitting stubout (fig.7.2), you will need a female PVC fitting.For a stubout with a copper female fitting (fig.7.3), you will need a male PVC fitting. In general, I like to use male fittings on the pipe portion that will be permanent (i.e. stubout) as female couplings made from PVC may crack if tightened too much.

STEP 2 – Apply purple primer, cement to the MIP side (not threaded) of the p-trap, then insert the NIBCO trap adapter. I placed the fitting upside down and pressed down on them for tight fittting (fig.8.1) (Note to NIBCO – please DO NOT apply hard to get off stickers on the gluing side! It took me unnecessary 15 minutes to scrape and sand off that label!)

 
STEP 3 – Now I needed to figure out a distance between the stubout to p-trap for my horizontal pipe so I temporarily attache the tail piece and p-trap together and screwed in the NIBCO 4 in. PVC DWV Street Spigot x FIPT Female Adapter. Whatever the measurement is, I usually add 1/2″ in extra length because I seem to lose about that amount when I solvent weld joints.
STEP 4 – With pipe cut to proper length, use purple primer + cement to glue it to the FIPT female adapter.
STEP 5 – Wrap some white Teflon tape to the stubout thread, then twist on the pipe+FIPT

STEP 6 – With the piece still attached, glue on the 90 degree elbow from the p-trap assembly.
STEP 7 – Finally attach the rest of the p-trap
STEP 6 – Do a quick newspaper-leak-test and you are done!

 
Unlike some other setups, the entire assembly (up to stubout) can easily be removed for maintenance.

With schedule 40 PVC, the setup is very strong so that accidental bumps will not cause it to leak.