My house is about 50 years old. All downspouts from the gutters go
into underground piping and exit "downhill" from a four-inch black
plastic pipe into a drainage ditch.
Near the end of last winter, noticed that water was pooling up from
"underground" near one of the downspouts.
Being lazy and clueless, ignored the problem. But as rain season
approaches, figured I better fix this -- we get about five feet of
rain per year.
I will dig out and see what is going on (I suspect a hole
underground). I will patch if I can, but if I need to run a new line,
I was planning 3-4-inch plastic pipe running in a shallow trench (not
much freeze problem here) downhill to the ditch.
However, when I installed a french drain behind a storage shed a few
years ago, all the manuals were very specific about "drop per inch" --
ie -- the pipe should gradually slope away.
That would be difficult here, as I would have to run the line about
200 yards at a diagonal to do this from my house on a hill.
If I run the drain pipe straight downhill it will be about a 30-yard
run, but quite steep. Is that a problem?
I'm not an expert on this, but I think the severe drop shouldn't be a
problem if it's a solid pipe. The water is coming off the roof
straight down, so the runoff pipe being severly sloped shouldn't be a
I think on some french drains where you want the water to seep out of
the holes on the sides of the pipe, then the pitch may be critical.
If the drain is TOO steep, you risk a siphon effect wherein rain is
literally sucked out of the sky! This will fill the ditch (irrespective of
its size) and the rising tide may wash away your home!
That said, how "steep" are your downspouts?
It might be worth it to rent a camera and inspect it internally. You could
have collapse, clogging with dirt/sand, or roots. If it is as simple as
dirt, you can just flush it. If it is a collapse, at least you know where
the problem is, and don't have to dig up the whole thing.
Even at 50 years, clay or good plastic may be still "good enough". You
could cut an access hole, insert a small hose, and push it down to jet
through the clog, or even come up from the bottom to flush out the
obstruction. Those sewer guys have a high powered jet that would blow it
right out while the camera is in there.
Build you a critter barrier on the end of the pipe, as sometimes when it's
not raining, this is a place where critters nest. 1/2" hardware cloth works
Fast slope is good. Helps keep if flushed out even during slow rains when
sediment and gook might tend to settle with slow flowing water.
Try free first. Use one of those little conical sprayers that you would use
to spray off your driveway. $1 at the Dollar Store. I'd try from the
bottom first. You'll know if you're flushing it out, or if it hits
something and won't go any further.
Not sure I understand questions, but I have around a dozen downspouts.
All pretty much come straight down from the roof. All go into clay
pipe openings (except one) and eventually connect to a big clay-type
underground pipe (maybe 6-inch diameter) that gradually slopes across
the yard and then down to the ditch. This runs freely at the ditch and
the mouth of the outlet is packed tight with pea gravel.
No problems at any downspout but the problem downspout.. The problem
downspout comes straight down from the roof, but does not enter a clay
pipe directly. It enters a thin-walled galvanized pipe that is set in
concrete and the pipe goes through a cement slab.
The pipe is near the edge of the slab and the water is bubbling up
from under the edge of the slab.
It has not washed out much soil yet, but this winter it probably will.
I could easily disconnect the gutter downspout from the "pipe in the
cement," and do some alternate type of drainage, but would prefer to
keep the old system if possible. Just not sure what I will find when
I get down there and start digging.
What Steve said. All you need is a long enough hose to go from your
outside house faucet to the far end of the drain pipe and then another
equal length to go from the far end of the pipe up into the drain line
to clear it. If you do get to a blockage and can clear it out, I
would still continue to blast the inside of the drain pipe all the way
to the house, that way you're starting clean and are good for another
I don't think there is anything to try, other than digging.
Since the water from the problem pipe is not "bubbling" back up and
spilling out over the top of the concrete slab, that indicates to me
that here is not a major block, but rather a hole just below the slab.
I posted some photos of the set-up on flickr. You can see them here:
Hope you can see that there is nothing to prevent "backflow" from
coming up back over the slab. All the other drains are running
fine....so....makes sense there is a hole just below the slab.
I took today and Friday off (West Coast), rain is set to return on
Saturday, so I had better go start digging to see what I see, but any
It looks like in the pictures that there is a metal reducer that goes
from the gutters down to the PVC in the slab. I would unscrew that
first and see if you can remove it. Then run a waterhose (or a small
pipe camera) to see if there actually is a hole.
OP again...Dug out around the edge and disconnected the downspout from
I can see into the hole. The one-inch steel pipe goes through the
slab and into the mouth of a three-inch clay drainpipe (the clay looks
and feels like red "brick" sort of material).
The clay is apparently clogged somewhere nearby, it does not take much
water to make the clay pipe back-up. When it backs up, it just spills
over the top of the clay pipe, which is set about two inches (more or
less) under the cement slab.
The water is then flowing away, creating a tunnel near the house.
I tried flushing with high pressure water from the top, but no luck.
Since the end of this drain is at least 100 yards away, maybe more,
and numerous other downspouts connect, I can't see any chance of
clearing this from below -- esp. since the clog appears to be fairly
close to the top. The water backs up pretty quickly.
Any other thoughts, other than running a new drain line down the hill
-- I think my snake would probably crack the pipe.
I don't think drain cleaner is indicated for clay pipes...
downspout lines appeared to be clogged. I tried putting a garden hose
through it with a nozzle shooting straight ahead. I got about 4' and it
stopped dead. I kept pushing and it finally went through. I was happy
until it actually came up into another downspout. So, these 2 were T'd
together ... not bad as one carries a water from a very small piece of
roof. So, I went in from that downspout and the hose went about 15 or
20' and stopped. I couldn't get it any further. So, I started
investigating on the internet and made a few calls. An auger would
definitely break the plastic pipe, so I found a company with a jetter.
The jetter is a super high pressure nozzle that sprays forward and also
backward. They were able to clear it. Previously, the drain would
overflow with the water from a garden hose. His jetter pushed out about
6 times as much water. However, about 15' in, he noticed there was a
semi-blockage. He suspected that the pipe was crushed. As he didn't
bring up and soil, he didn't think there was an actual hole in the pipe.
We did, early on, have many truckloads of dirt brought in. That may
have crushed it. Or even maybe when the house was built. The drain now
takes water, however, on heavy downpours it will overflow a bit. So, we
have to dig and replace the crushed section. BTW, the jetter guy
charged $150. He said it would be about $150 - 200 to fix it depending
on if there were multiple crushed pieces. There are companies that
sell jetter hoses and nozzles that you can attach to a power washer. I
think with the number of these drains going from my house, I am going to
invest in it. I already have the power washer, so for under $200, I
could get everything I would need. Of course it wouldn't be like the
one the pro had. His pumped about 7 or 8 gallons per minute at about
2500 PSI and was mounted on a trailer. My pressure washer, while having
about the same pressure, only does about 2 GPM. But it should help to
clear these lines of leaf and dirt matter.
Hope this is not a double-post. I posted some 20 minutes ago, and
Steve, I did not ignore everything. I think I did try everything
suggested here EXCEPT water blasting from the bottom of the hill.
did not try that because I am afraid I might clog up something that
would screw up the 11 working downspouts.
So, I do appreciate everything everyone suggested. And I did take
apart, waterblast from the top, etc as suggested, except for the one
Again, if I have to trench, I'd rather do that than risk screwing up
the rest of the system.
Yep, I'm a pain....
Well, decided to try the snakes....Tried my standard "manual" snake
and got it down about a foot or so.
So, then went to my closet auger (manual power again). About half the
diameter of the standard snake, I managed to get all 15 feet of it
down the drain....about three times.
Went back to the standard snake. Managed to get it down about 12 feet
before it would go no further.
Water is draining a bit better, but still pretty slow.
I may bite the bullet and call the local Rooter/Septic/plumbing
company and ask if they might be able to try something.
Otherwise.....hi ho, hi ho, it's a 30-foot trench through extremely
rocky hillside....Fun. Hope my mattock and I are up to it.
Okay. I'll bite. You dig it up. It's in the middle of a section of pipe.
Now what? Break the pipe? Feel warm and fuzzy that the clog is so close?
Cut and repatch in enough places to be able to get that section out? Seems
like a lot of work instead of using something common like a garden hose.
Now, to refill, and replant the lawn............................
When a water main or sewer line breaks, the city doesn't replace the entire
piping system. They install a patch.
What with over 1,000 water main breaks in my town this summer, I've watched
a few. They dig down to the break, cut out the offending section, and
replace it with a suitably-sized plastic pipe. The ends of the plastic pipe
are attached to the original with a rubber boot and (looks like) stainless
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