Downspouts into 4" Drain Pipe
Eric Keller
asked and answered.
I plan on burying my downspouts and having them merge into one 4"
drain pipe. The discharge will be at a nice point far from my house.
The length will be about 200 ft from the first downspout to the
discharge. There will be a total of 4 downspouts merging into the same
line.
My question is: How many downspouts can I run into a single 4" PVC
pipe within the 200 ft length? I live near Chicago and we get plenty
of rain.
Thanks.
aemeijers
> snow and not thaw until April.
>
> IMO- you need to go either with at least a 8" pipe or use shallow
> ditches to prevent freezing. The number of downspouts doesn't
> matter-- the surface area that you're draining does.
>
> I've got a 12" culvert that takes the water from one side of a 2-car
> garage. It has a smooth bottom is well pitched and is on the south
> side of the garage-- but it gets 1/2 full of ice sometimes. I'm
> glad I didn't use 6" pipe.
>
> Jim
Gonna be fun getting a leaf dam out of that 200' drain line, once a twig
gets crossways in the pipe, and jams in a seam at the 100' mark.
If you MUST take your downspouts below ground (and it is seldom a good
idea, IMHO), run them into a collector box, with the outlet pipe halfway
up one side. Make sure the lid is something you can lift off by
yourself, and that you can reach down far enough to clean out the box
once a year or so. Your local concrete flatwork company will have all
the bits you need- this is standard commercial/parking lot stuff.
The traditional method of proper pitch to the finish grade near the
house, and splash blocks, works much better IMHO, and is a lot cheaper
and easier to take care of. At least you are running them away from the
house- idiot previous owner here ran them straight down to the
(basically dead) foundation drains. Guess where the water ended up? I
sawed those off and added elbows before I even closed on the place. My
sister& BIL's place had a buried drain, and the PO either didn't know
how to slope a drain line, or the ground heaved. One failed joint right
below the downspout, and it all ended up in the paneled basement,
starting high on the wall. (It gave my sister, a world-class SWMBO, an
excuse to make him gut and remodel the basement the way she wanted it...)
--
aem sends...
Eric Keller
aem,
Good point about the distance. I was concerned about that so I am
planning a having few cleanouts. I also plan to splice in a "tee" into
each downspout before they go under ground. That way if the system
backs up or gets clogged, water that backs up the system will flow out
the tee in the down spout. Plus I'm using pvc and not corrugated pipe
so I can run a snake if needed. Less chance for that twig to get
caught too.
My yard gets very wet and the drainage is not the best. Any water in
my yard goes to my basement and my sump pump runs about every 3
minutes certain times of the year. I'm also planning a french drain to
divert the underground water which is a bigger problem. So I think
this is the best thing.
Regarding the collector box you mentioned. I like that idea. Can you
point me to a website? I did a search but couldn't find anything. Is
there another term to use? I tried "collector box" and "filter box"
without much luck.
Thanks.
Art Todesco
situation. Each downspout runs into its
own flex 4" line, underground to the
edge of the hill. The house is set into
the mountainside. The one place where
the 1 for 1 was not done, was for 2 very
short pieces of gutter, approximately 5'
each, each with its own downspout.
These run to the edge of the hill
through a single 4" line. Also, we
don't really have a frost line here, so
it shouldn't freeze. I used to live in
the Chicago suburbs where everything
froze. I can't tell you how many time
my sump output froze. Unless you can
get it deep and very vertical
underground, it'll probably freeze.
Eric Keller
Thanks for the freezing tip. But it will only freeze if water is in
it. If I install it right then after it rains the system will be
empty. Your sump pump output must have had a low spot where water
collected and froze. We have had a very cold winter and mine has been
fine. Even if it does freeze, I'll have "tees" spliced into the
downspouts so the water will back up and flow out the tees.
BTW, I used to live in the Sacramento, CA area. Had no real concept of
the freezing line until moving out here. i think it's something like
3-4' here and my guess is back home it's 4-6".
aemeijers
the top, but solid lids are also available.
--
aem sends...
Michael B
a tiller and a string level, making a gentle and manageable
drainage swale. With plastic from the house, out about 8 feet,
and the dirt used to make a positive slope from the house,
covering the plastic far enough so it gets away from the house.
But anyway, you can convert to 3" pipe after the downspout
transition. Easier to bury. Use good leaf guards up above.
willshak
I have two roofs on my 60' long house, one higher than the other. The
one end of the house has level ground, the other has a fairly steep
slope dropping away from the house. The upper roof gutter drains toward
the sloped side of the house, and when it reaches the end of that roof,
it drops via downspout to the lower roof's gutter, then into the lower
roof gutter, then along that lower gutter to the sloped side of the
house. It then drops down a downspout to the ground and into a 4"
plastic elbow connected to a 4" pipe which exits about 30' downhill from
the house. It's been there for 26 years with no problem, except for the
chipmunks occasionally building nests in the pipe, but they are flushed
with the rains.. The same type system is at the opposite side of the
houser, so we're talking about 120' of gutters between the 2. It has
never rained hard enough to overflow the gutters, unless blocked by
leaves or debris, which can happen to any length of gutter that is not
cleaned regularly.
Without doing a lot of math, I doubt whether 4 downspouts draining into
a single 4"' pipe would cause a problem with a standard sized house.
Math would give you the total volume of each downspout x 4, and the
total volume of a 4" pipe, and even if the volume of the 4 downspout is
more than the volume of the pipe, the downspouts rarely, if ever, have
to deal with a full volume of dropping water. If it ever does, somebody
better be building an Ark.
I have checked the flow of water from the 4" round pipe during a hard
rain, and the depth of the water coming out was about 1" to 1-1/2" deep
from each of the two gutters
--
Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeroes after @
Art Todesco
in my case. I 1 1/2" going underground
and it froze once where it came out at
the property edge. Now the house has
a 4" line going from the house to the
property edge, downhill. The 2 pumps,
120v and 12v, come out from the basement
and go loosely into the 4". The 4" is
large enough that, even in below 0
temps, it will drain. But, I could see
a situation, which snow and ice near the
exit point, where is could dam up and
freeze. But, that's the new owner's
problem now.
Art Todesco
> Eric Keller<eke...@bethpc.org> wrote:
>
> -snip-
>>
>> My yard gets very wet and the drainage is not the best. Any water in
>> my yard goes to my basement and my sump pump runs about every 3
>> minutes certain times of the year.
>
> every time it rains& your neighbors are pumping their basements?
>
> Then dig deep enough for your cellar to drain to daylight without
> those pumps. Size the drain to take your roof runoff& inside and
> outside perimeter drains. Solved freezing, and cellar dampness with
> one job.
>
> You sound like you're fighting the idea of going bigger than 4".
> Don't. It is too small volume-wise[unless you have a very small
> house], freeing-wise, and clogging-wise.
>
> If you can't afford to do it right, save your time and money until you
> can.
>
> Jim
The one thing that's nice about living
on the side of a mountain is that if
there should be water in the basement,
you just open the door .... it's all
downhill from there.
Harry K
I did that at my house but only had to run about 30 ft to surface it.
At the only entrance to the drain pipe, I transitioned to a 6" collar
and cut a cirlcle of 1/4" hardware cloth to fit inside. After leaves
are down and gutters cleaned, I just lift the circle of hardware cloth
and dump the crud....hmm...I have forgotten to do that for several
years now. Better check it today!
Harry K
Eric Keller
Bill,
Thanks. Feeling much better about my decision. I thought about going
up to 6" pipe after the second downspout or even running two separate
lines each taking on two downspouts. But all that is too much work..
and material. I do think that 4 downspouts running into one 4" pvc
line is adequate. Your experience helps me make my decision.
Erma1ina
I whole-heartedly agree with aem as far as NOT taking the output from
your downspouts below ground.
I'm in east central Iowa -- climate similar to the Chicago area. In
winter, the snow melt and/or freezing rain will not run through the pipe
fast enough to avoid freezing in a shallow 200 ft. line, even a 4" PVC,
especially in a winter like we've had this year. The ice will accumulate
and block the line. I doubt any number of cleanouts will enable you to
clear that line once it's blocked.
If you MUST proceed with your plan to route the downspouts underground,
in winter you could use the cleanouts to dump deicer (calcium chloride
pellets) into the line to PREVENT a freeze-up. This winter -- with heavy
snow and freezing rain and many deep-freeze/melt cycles -- that's what I
did with my sump pump discharge line, a 1.5" PVC feeding into a
dedicated 60 ft. 3" PVC exterior drain line. I have a cleanout (one leg
of a "Y" fitting) where the sump discharge exits the house and enters
the 3" PVC line; the discharge immediately flows through deicer dumped
into the cleanout and carries the pellets down the line. It worked well
but it was a bit of a PITA keeping a good supply of deicer in the line
at all times and that was with only a 60 ft line that served only the
sump discharge.
HTH. Good luck.
Eric Keller
Thanks. I think you missed the part of me placing tees in the
downspouts to deal with just that. BTW, good idea on he salt.
Tony
I was just going to suggest using PVC and not the black corrugated
flexible stuff, but I see you got that covered. 4" PVC will carry a
hell of a lot of water.
glernt...@gmail.com
glernt...@gmail.com
glernt...@gmail.com
trader_4
it's going to do much good either, unless the frozen part is right there in
the sump. If it's frozen 6 feet away, how's the CC going to get there?
If it gets there, then some water must be flowing and once water is flowing
it will clear itself. If any water is flowing, hot water would work faster
and better.
gfre...@aol.com
wrote:
to have a pretty good pitch to it.
trader_4
pipes for example are 4" and support not only clear water but solids too.
Also it's not about the number of downspouts, it's the roof footprint
that they cover. There are probably some online resources that tell you
how much water a given roof will generate during a heavy downpour. It's
not the roof plane area, it's the flat area of ground that the roof covers.
If in doubt, given all the work involved, I'd consider running a 6" line.
Probably be a good idea to have a clean out come to the surface every 50 ft
or so too.
gfre...@aol.com
pipe. When it comes off the roof it will have plenty of velocity but
that will go away pretty fast in a near horizontal run.
trader_4
further than 200 ft.
gfre...@aol.com
pumps unless you are talking about a city on a hill.
Water still moves pretty slow in a sewer or a storm drain.
Hey if he wants to try it, go for it but I doubt he will ever serve
more than one downspout and even then, in a heavy rain, water will
back up in that 4" pipe unless he has a whole lot of slope on the
line. (1/2" per foot or more).
This is just based on what my neighbor found running about 40' of 4".
It could also be it rains harder here I suppose.
terry
--
For full context, visit https://www.homeownershub.com/maintenance/downspouts-into-4-drain-pipe-430220-.htm
micky
>I have 6 downspouts going into a 4 inch pvc pipe,the total length at furthest point is about 225 feet..just finished it a couple days ago..will see how it works..I hope I don’t have to dig it all back up.
what roof area they drain.
Clare Snyder
much drop to "daylight"? 1000 squre feet would overflow that pipe in
a good rainstorm here.
gfre...@aol.com
wrote:
pipe?
micky
here for a while but I finally found the far end of the 4" corrugated
pipe. I cleared some medium sized rocks from it and some dirt that
was making a lake where it emptied and I think I'm in good shape now.
Although I'll check again when the water table is higher and the sump
pump puts out more.
Also, the pipe went under the "easement" the path outside my fence,
beside or behind all the houses, and the foot traffic, mostly me and one
other guy, and only occasionally when he moved the lawn mower from his
back yard to his front yard and back, wore away the dirt over about 4"W
x 8"L of pipe and then further stepping on it made 4 small holes. When
it was clggoed at the end, there were 4 thin streams spurting out, one 2
or 3 feet long.
I don't think that will be as much of a problem, but just today I used
some Flexseal (?? The one where he tapes the boat back together) and
then buried it with an inch of dirt. We'll see if the path continues to
be wet after the sump pump runs. (If it is, it's not so terrible. The
new dirt is more important because no more footsteps right on the pipe.)
I'm going to find a flat rock to make a roof over where the pipe ends,
but it lasted 42 years the first time, even without that. .