# Stormwater -- Drilling for a PVC snap-on Tee fitting **URL:** \ **Category:** Factual Questions\ **Created:** [October 10, 2020, 11:50pm UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673 "2020-10-10T23:50:10Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [October 10, 2020, 11:50pm UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673/1 "2020-10-10T23:50:10Z")
I can get a snap-on T fitting for my stormwater drain: it seems to be a fairly standard part: [https://www.holmanindustries.com.au/product/storm-pvc-snap-tee/](https://www.holmanindustries.com.au/product/storm-pvc-snap-tee/) I can snap it on, and I know how to cement PVC, but I don’t know how I would cut out the pipe where the fitting snaps on. Have you ever done this? Have you ever seen it done? I saw a reference to ‘drilling with a diamond drill’, but I’m fairly sure they were talking about adding a snap-on to a ceramic / vitrified clay pipe. I just want to snap on to a 90 mm PVC pipe \*random observation: I can get a T junction in 100mm, or a snap-on for 90mm. Evidently our standards process differentiates 90mm as being the stormwater size. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 11, 2020, 12:04am UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673/2 "2020-10-11T00:04:47Z")
You should be able to glue the fitting on to your existing pipe, then use the opening in the tee as a guide for a hole saw (attached to a drill) of the appropriate diameter to cut out an opening in the existing pipe. This would likely produce the best result. If you can’t find a hole saw with the right diameter, maybe use a Dremel-type tool with a sideways cutting drill bit instead, but this would likely produce a rougher cut opening. With that said, most plumbers would likely not use this part, but would instead simply cut the existing pipe and glue a tee in place. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [October 11, 2020, 12:15am UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673/3 "2020-10-11T00:15:19Z")
> [@robby](#): > > With that said, most plumbers would likely not use this part, but would instead simply cut the existing pipe and glue a tee in place. I’m thinking this would be easier to install: > **[STORM PVC JUNCTION - Holman Industries](https://www.holmanindustries.com.au/product/storm-pvc-junction/)** > > The Holman Storm PVC Junction is for use with Stormwater pipes. Available from 75mm to 375mm. Complies with AS/NZS1254 - AMI 70007 They apparently have junctions available in both 45-degree (shown here in the preview) and 90-degree angles. ---
**Author:** ![RedSky](https://avatars.discourse-cdn.com/v4/letter/r/67e7ee/32.png) [@RedSky](https://boards.straightdope.com/u/RedSky)\ **Post date:** [October 11, 2020, 7:27am UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673/4 "2020-10-11T07:27:10Z")
I’m not familiar with that part however it looks like you could just use a hacksaw to cut a v to match the fitting. If you need a round hole then a twenty dollar hole saw kit is fine for PVC or wood. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [October 11, 2020, 11:23pm UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673/5 "2020-10-11T23:23:33Z")
Ok, a hole saw looks reasonable – I’ll have to measure and see what I can buy, because Holman doesn’t seem to have any installation guides that I can find, and I don’t have any 70-90mm bits. (Also, the stores are closed for quarantine, and I have to buy sight-unseen). The stormwater drain that I want to tap into is buried, so adding a T junction would involve digging a larger hole and also fitting a new piece of pipe to get a gap and an end I could slip onto. That’s required for pressure fittings, but I hope the hole saw will be less work. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [November 2, 2020, 7:19am UTC](https://boards.straightdope.com/t/stormwater-drilling-for-a-pvc-snap-on-tee-fitting/922673/6 "2020-11-02T07:19:32Z")
Ok, I got a cheap hole saw and drilled it. Observations: - When I dug down, I found the 90 mm pipe inside a 100mm pipe! I was just a foot or two from the nearest downpipe, so maybe they used a 100 T and some 100mm pipe and slipped in onto the 90mm pipe somehow – it’s storm water, so it doesn’t even really have to be sealed. - The pipe seems to be partly blocked at the next downpipe. I’m going to dig another hole and have a look. - When drilling on a PVC pipe, you need to either drill a hole rather smaller than the pipe, or have a _very deep_ hole saw. a 99mm hole in a 100mm has to be 50mm deep, because that’s the radius of the pipe. If the hole saw isn’t that deep, it’ll bottom out. ALSO, for the last 10~20 mm, you’ll be cutting tangentially through PVC. I didn’t try to cut a 100mm hole, but I had to cut out a smaller hole first, to get a little more depth, and I still had to break out some of the pipe I found myself cutting into.