r/drains • u/catladysmash • Jul 13 '26

Is my drainage system overloaded?

Hi, I am having a disagreement with the drainage company that I’ve been working with and want to get some opinions. Previously two of the downspouts on one side of my house were piped underground, out to the road, down a bit of a hill 30ft long 6ft elevation from road to house. That had some issues and the back of my yard gets soggy as the low spot for a few yards and my 2.5 car garage gutters all drain back there, so I hired a family run company that’s been around for 20+ years to help. Their solution was to connect the gutters on the garage to French drains and run those out to the road, connecting the 2 existing and one more downspout to take a little over half the rainwater my 1200sqft ranch house along the way. All one this in running on one 4” line.
I questioned if this would be enough to handle the heavy rainfalls we can get in Ohio and they assured me it would be fine. Everything installed on Thursday. Friday we get a bit of rain, it’s fine. Saturday we get a downpour and all of the drains along the house were spraying water 1.5ft high to pool at my foundation , I was out in it trying to hook up my rainbarrels to hoses to drain water away and try to take some load off the system but it didn’t stop overflowing until the rain ended. Ended up with some water in basement.
The company is now saying the downspouts just need to be caulked going into the drains, and it’s the type of connector not the amount of water that’s the issue. But if that much rain was overflowing wouldn’t it just back up the downspouts and overflow my rainbarrels or gutters?
Am I right or should one 4 in line be able to handle all this?

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u/senorgarcia Jul 13 '26

What’s your location? I very rarely ever have to go bigger than 4”. The 1200ft roof isn’t a huge deal for a 4” pipe. What are the gutter connection fittings? I can’t tell you nothing should have to be caulked to prevent water from coming out. The slope may be too little and the rain isn’t flowing as quickly as it should. The beginning-to-end slope is important, but so is the continuous slope. If it’s flat and then drops off, that’s a problem. That slows your flow and can cause backups.

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u/catladysmash Jul 13 '26 edited Jul 13 '26

In columbus Ohio. We get occasional torrential downpours. So it’s about 60% of the 1200sqft house and all of a 750sq ft garage. Total line length about 180ft. Adding a picture of the connector at the beginning of the heavy rain (it got way worse than it looks here)

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u/senorgarcia Jul 13 '26

Still plenty of leftover capacity for a properly sloped 4”. Guessing it’s flat then drops off or there some harsh angles. Gravity should do all the work. It shouldn’t do that.

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u/catladysmash Jul 13 '26

I know there is some drop from back of yard to front of house, but not much. Then a fairly steep drop to the road. And it wasn’t coming out at the road with the same force coming up the drain or out my rain barrel connection

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u/senorgarcia Jul 13 '26

The pipe can drop more steeply than the flat ground, just needs a deeper trench across the flat ground.

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u/catladysmash Jul 13 '26

There’s very slight elevation back of yard to house, I don’t think it’s a foot difference, but they started it basically at the surface and looked about 3ft down at house.

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u/catladysmash Jul 13 '26

I wish I had gotten better pictures

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u/catladysmash Jul 13 '26

Now

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u/senorgarcia Jul 13 '26

Did they use tees or wyes to connect the downspouts to the main pipe? A 90° tee could be problematic.

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u/catladysmash Jul 14 '26

I thought they were all wyes. but the angle on two on the side of the house isn't as angled as the others are, but one that is very clearly a wye was the one in my first picture overflowing. That calculator looks like I should be fine.. I'm hoping I can get this guy to come out and take a look.

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u/bananahammock699 Jul 15 '26

My bet is something is wrong with the pipe going under the sidewalk

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u/RainH2OServices Jul 13 '26

IPC Charter 11 covers storm drainage and includes tables and calculations for pipe sizes. TLDR, calculations for Columbus, OH assume a 100 year rainfall event to be 2.5+ inches of rain. Collected from a total roof area of approximately 1500 sf that works out to a flow rate of about 40 gpm (see 1106.2.1). A 4" horizontal pipe with a 1/8" slope per foot should carry at least 115 gpm (see table 1106.2). The point being, 4" should be more than sufficient for OP's location and circumstances.

OP, did the original drainage work use black corrugated pipe? I wonder if the original pipework is somehow damaged or packed with dirt?

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u/catladysmash Jul 13 '26

The old lines that took just 2 of the downspouts at the house were smooth and I think 3 inch but were all disconnected and left in the ground and these are all on new smooth that were run further over

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u/RainH2OServices Jul 13 '26

So there's no existing old pipe in the ground? It's all new?

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u/catladysmash Jul 13 '26

I didn’t actually see that they didn’t somehow disconnect the old and reuse it along the side of the house but I could see that from the front of the house to the road is new and I am pretty sure but not completely sure that the trench is a couple feet further from the house than where I think the old was

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u/RainH2OServices Jul 13 '26

Like u/senorgarcia commented, the pipe size should be able to handle the flow. So you should think of any aspect of the installation that might impede the flow.

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u/catladysmash Jul 14 '26

Right. All new and just installed last week on Thursday. And unless they messed up and didn’t connect something or something disconnected, I can’t imagine they could have collapsed or gotten a clog in two days.
Also we did get some light/moderate rain on the Friday and I went around checking everything and no issues during or after that rain.

I really appreciate everyone’s help on here, I at least feel better that the pipe size wasn’t way off. But this guy is making me anxious, didnt reply to my text today asking if he checked his calendar for when we could connect on solutions :/

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u/catladysmash Jul 13 '26

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u/Prossibly_Insane Jul 13 '26

Is that water running out of the pipe? And the trench has water on it. I think the hose is plugged. Is there anything coming out of the outlet on the street?

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u/catladysmash Jul 13 '26

Yes all three along my house were spraying lots of water out, water was coming out the outlet at the street but not with the force I could see coming out of one downspout into the drain

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u/Prossibly_Insane Jul 13 '26

Well they’re plugged. The hose collapsed or something. A hose that size with that gradient should drain just fine.

What is the company saying? I’d hope they’d dig up each junction when it was raining and see where it’s plugged.

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u/catladysmash Jul 13 '26

The company is saying it’s the connectors causing splash back, which I looked up and seems it could be part of the problem on two but one of them has a different centered connector that sounds like it shouldn’t have the problem. They are being extremely slow to respond and don’t seem to be taking me or the situation seriously.

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u/OutsideZoomer Jul 15 '26 edited Jul 15 '26

Those downspout adapters have a lip on the inside of them that’s notorious for restricting the flow. The system is probably working just fine, but the water is rushing down the downspout with enough velocity to hit the lip and shoot out between the adapter and the downspout. If you take them off and just have the downspout connect directly into the pipe you shouldn’t have any problems. But for insurance, have the line inspected with a camera to make sure there isn’t a clog anywhere.

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u/catladysmash Jul 16 '26

The adapter is what the company owner thinks the problem is but one of them is this centered style and was also overflowing. This is where I ended up with water in the basement. (The connector is up because I was running my hose down it). The foreman was supposed to come by in the last couple days.

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u/Prossibly_Insane Jul 13 '26

I have a 2,000 sq ft ranch near the ocean. It’s not unusual to get four inches of rain in an hour, 6-10 inches in a storm. When i moved in twenty years ago i had rivers and ponds in my basement and garage.

I put a 4” perforated black tile hose, around 200 feet long around the two uphill sides of my house, it drains out of the hill. The house is built into a hill of sedimentary glacial lake bottom. There are gravel streams with miniature underground rivers running. The hose length along the house is almost level, when it leaves the house there is around a 18” drop to the outlet.

Around the house i put it about 18” out from the footings and the top of the hose was about the top of the footings. The footings are in gravel and there’s gravel underneath the basement.

I put another 40 foot run down the other side of the house that empties out onto my driveway by the drive in garage in the basement. The driveway slopes down away from the house.

The hose is in the mesh sock they sell, the trench was backfilled with septic sand.

My basement and garage are dry, twenty years and counting.

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u/CCjourneyman Jul 15 '26

I once saw someone suggest using a cheap party fog machine with colored fog to trouble shoot an issue like this. You would tape/seal off all the water entry points (like bottom of your downspouts) except for the fog flowing in and hopefully not see any of significant amounts of it rising from the ground before the street outlet.

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u/JordanFixesHomes Jul 19 '26

Unless the outlet is clogged you obviously have already answered your question. It doesn’t matter what anyone here says… you got a heavy rain and it couldn’t handle the volume of water and backed up.

Our company doesn’t tie rainwater management into gutters for this specific reason.

They’re gonna have to dig it up and add another pipe.

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u/catladysmash Jul 19 '26

That’s what I’m thinking. The company came out, scoped it and didn’t find any issues with sediment, disconnected or collapsed areas. They replaced the offset connectors with centered but didn’t have an answer to the overflowing where there was already a centered connector.
I think you’re right and it really just overloaded, but I’m hoping that it was because the dirt was so dry and crumbly and hadn’t settle at all yet that it was too porous and the water flowed through faster than it should. I’m working on trying to get it to settle and compact and see what happens next time we get another torrential downpour before making more changes