Jim Elbrecht wrote:
Eric Keller wrote:

My first post to this group so please forgive me if this has been
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.

And ice. I suspect a 4" pipe will freeze up a week after the first
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...