What is the minimal connection required for PVC pipes draining a sump?

Question

I'm adding a backup sump and will join it into the existing discharge pipe, with a check valve for the backup pump separate/before the pipe series merge. In this question I asked about bonding agents or techniques for the PVC pipe: What does an average home owner do for pipe compound when only a small amount is needed? Here, my question is, what is the minimum bonding needed?

I take it dry fitting the pipes together is insufficient because when the pump is on, it's a little like the pipes are under pressure (from air and then water). There's also leak prevention needed, considering some water will sit in the pipe against the check valve. But in that other Q&A, someone said one-part glue is an option but not as good. So I'm wondering, what is the minimum (as in, code compliant, reliable) type of bonding between pipes in this application and why? Given the risk of having to service this in an emergency, less feels like more, so long as it's not adding to risk of emergencies/problems in the first place!

Answer 1

When making stuff out of PVC pipes, use PVC solvent. As simple as that. You have noble intentions but in this case, it's just setting yourself up for failure. The solvent and primer doesn't need to come fresh from a store - be creative!

1. Look on local Craigslist and FB marketplace. Plenty of DIY types know about the short shelf life of pipe solvent, and may be giving it away or selling for a couple bucks.

2. Advertise on CL and FB marketplace that you'll pick up a used but at least half-full bottle of solvent and primer for a fiver from anyone willing to part with that.

3. Ask your neighbors.

4. Ask a farmer if you live where there are farms. Established farms are like mini hardware store stockrooms, but with not much stock rotation :)

5. Just buy the thing. After using what you need, advertise that it's available for pickup for $1 or $5 as above. Probably better than advertising for $0 since there are lots of people who will contact you then not bother showing up. It'll drive you nuts. Once someone shows up, you can then give it away for free if you feel like it.

There's another consideration for trying to have low ecological impact or low waste: Every hour of being alive has an environmental and resource usage cost. Don't forget that. It takes some amortized amount of food, drinking water, gasoline/diesel, sewage plant's processing capacity, medical care, recreational facility use (whether local or remote vacations etc.), and so on. By expending a couple hours chasing leftover glue and pondering about it, you have already obliterated any "savings" by expending those resources that people not think about. And, sometimes, the "savings" are far from. See the excerpt from Joel Spolsky's essay "A Field Guide to Developers" that I've included at the end of this answer.

Finally, if you're pumping the water from the sump up, make sure to install a check valve in the bottom half of the riser. It'll prevent the riser from draining back into the sump when the pump turns off.

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September 7, 2006 by Joel Spolsky

A Field Guide to Developers

excerpt

Let me, for a moment, talk about the famous Aeron chair, made by Herman Miller. They cost about $900. This is about $800 more than a cheap office chair from OfficeDepot or Staples.

They are much more comfortable than cheap chairs. If you get the right size and adjust it properly, most people can sit in them all day long without feeling uncomfortable. The back and seat are made out of a kind of mesh that lets air flow so you don’t get sweaty. The ergonomics, especially of the newer models with lumbar support, are excellent.

They last longer than cheap chairs. We’ve been in business for six years and every Aeron is literally in mint condition: I challenge anyone to see the difference between the chairs we bought in 2000 and the chairs we bought three months ago. They easily last for ten years. The cheap chairs literally start falling apart after a matter of months. You’ll need at least four $100 chairs to last as long as an Aeron.

So the bottom line is that an Aeron only really costs $500 more over ten years, or $50 a year. One dollar per week per programmer.

A nice roll of toilet paper runs about a buck. Your programmers are probably using about one roll a week, each.

So upgrading them to an Aeron chair literally costs the same amount as you’re spending on their toilet paper, and I assure you that if you tried to bring up toilet paper in the budget committee you would be sternly told not to mess around, there were important things to discuss.

On a personal note, I've got a surplus Aeron for my home office in 2018. The only signs of wear are dust in some nooks and crannies, and scuffs on the wheels. Yes, it did take way more resources to make an Aeron than a cheap office chair. That Aeron will stay out of the landfill for a very long time, and it will save resources in the long run and that's what counts.

Answer 2

As far as I know code doesn't address sump pump drains beyond local code often forbidding draining them into sanitary sewers.

No, dry fitting will not work. PVC adhesive is cheap compared to the pipes, never mind the problems you are trying to remedy and prevent.

Unless you have an unusually strong pump or are lifting the water farther than usual, I suspect any good PVC adhesive will be more than sufficient. When assembling mine, I used the purple goop, which is basically a chemical weld; it held perfectly well through a situation where I was pumping out 8 gallons of water a minute.

The only thing you are likely to have to service in the middle of an emergency would be if your pump fails. The solution for that is to attach the pump to the exhaust pipes with a coupling of some sort that you can disassemble and reassemble rather than gluing the two together. I used a rubber coupling with pipe clamps, which may also have the advantage of providing some vibration isolation.

Note that if you are in a situation where you know the pump is going to be running on a regular basis, you probably want to think about a backup.

Now that "hundred year floods" are averaging 50 years or less, I have been meaning to install a Venturi pump as a permanent backup. These do not pump as quickly, but this backup would work even if I lose electricity since it is powered by water pressure from the municipal supply. They drawbacks are of course that they waste drinkable water, and they aren't as powerful as electric pumps. Until I get around to that, I have a spare pump on hand, fitted with a flex hose so I can toss it into operation or loan it out as needed.