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Cut and Dry-Fit New Pipes — Cut and Remove Pipe Section

Intermediate20 hours

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How to Install a Backwater Valve to Prevent Sewer Backups · Step 3 of 6

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Before applying any permanent adhesive, plan your new plumbing layout. Measure and cut the required lengths of PVC pipe. Use a saw for the cuts and then deburr the inside and outside edges of each cut with a knife or rag to ensure a smooth surface for a better seal. Assemble all the pipes and fittings without glue (dry-fitting) to check for proper alignment and length. This project aims for a more efficient layout with fewer sharp 90-degree turns, using two 45-degree elbows to create a smoother sweep, which improves water flow.

Goal: Plan and Measure New Pipe Layout

  • Always dry-fit the entire assembly first. This is the most important step to prevent costly mistakes with quick-setting glue.

Used in this video

  • Reciprocating Saw (brand: DeWalt, Tool Type: Power Tools, Power Source: Battery-powered)Cutting new PVC pipes to length.
  • T-shirt (brand: Unknown, Tool Type: Cleaning Tools, Power Source: Manual)Wiping and deburring the edges of cut pipes.
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FAQs

Is installing a backwater valve a feasible DIY project, or should I hire a professional plumber?

This is an intermediate-level project requiring significant physical labor, specialized tools (like a concrete saw or a heavy-duty sledgehammer for breaking concrete), and a good understanding of plumbing codes and concrete work. While possible for experienced DIYers, if you're not comfortable with breaking concrete, excavating near sewage lines, or ensuring proper slope and sealing, it's highly advisable to consult a licensed plumber. Improper installation can lead to leaks, blockages, or failure to prevent backups.

What permits or inspections are typically required before starting this kind of major plumbing work?

Absolutely, permits are almost always required for altering your main sewer line. You'll need to contact your local municipal building department or plumbing authority to understand their specific requirements for plumbing and excavation permits. Failing to obtain permits can lead to fines, stop-work orders, or requiring you to remove and reinstall the work if it doesn't meet code. Plan for inspections at various stages, such as after excavation and after the valve installation but before backfilling.

What are the most critical safety precautions I should take when breaking concrete and working with sewer lines?

When breaking concrete, always wear safety glasses, hearing protection, work gloves, and steel-toed boots. For working with sewer lines, always wear impermeable gloves (like nitrile or rubber) and a mask to protect against biohazards and odors. Ensure proper ventilation in the work area. Be extremely cautious of other utility lines (water, gas, electrical) that might run through the concrete slab; call 811 before you dig to mark utilities.

What size backwater valve do I need, and are there different types or brands I should consider?

The valve size must match your existing main drain pipe, which is typically 3-inch or 4-inch PVC in residential homes (e.g., Oatey 3 in. or 6 in. valves are listed as materials). Visually inspect your drain pipe to confirm its diameter before purchasing. There are two main types: normally open (most common, stays open until activated by backpressure) and normally closed (requires manual opening for regular flow); ensure the valve you choose is suitable for your application and approved by local plumbing codes.

Transcript
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Now we're going to take our PVC, hide it out. I'm sharplet right there. I like to do it in parts. I don't like to do it all at one time because you only have so much time since you put in the pipe and the glue. So we're going to always like to put in this one first. It's the easiest one. This one doesn't matter what direction it goes or anything like that. We have clear PVC cement and clear PVC primer. You always, always, always want to use primer. Make sure you have channel locks ready or some type of pliers open these lids. Now the clear primer is a little tricky. You have to remember where you primed everything. Let's see, it'll actually take off the writing and ink first. Maybe I'm going to keep this in the pipe. Now we're going to put in our glue. I like to put the glue on both fittings that we're putting on. Found it here. And ideally you want to put your pipe in and twist it to get a solid fit. It's like the dry fit everything before you start. Make sure it's going to line up. You need a fitting right here, right? So we're going to go ahead and glue this in because that doesn't matter what direction it goes either. Go ahead and prime the inside of both sides of this. Go ahead and prime this one more time. I'm going to put our glue in just on the bottom side. This one we know it has to go all the way down. You can see since I put that primer on there, it's going to stick with your fittings if you are dry fitting them. Oh, that's not good. So with the primer, I'll just do it again just to make sure if I'm not 100% positive it was primed. I'm just going to build it from here. I need to cut a new piece for here. This is where things start to come together. We're going to put our pipe coming out of the filter to the pump. Go ahead and glue it in place. Primer first, then glue. We're going to use our channel locks going straight across to get a straight line. We're going to put our elbow on. We're going to prime it and glue it just the bottom. Put our other elbow on to have a straight line across as a point of reference. We're going to put our pipe up, cut a pipe to size, the fit between these two. Use our shirt to get the snags off the pipe. Now when you're gluing multiple things, you always want to make sure you have everything planned out. In this case, we need to glue all three of these at the same time to make sure if we need any wiggle room we'll have it. Once the pipe is dried, it is very stiff and you cannot move it. Make sure you prime and glue…

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