Wells, Sump Pumps and Septic Sewage Systems - Drywell Construction

I'm going to be constructiong a drywell in my backyard to accept the water from my sump pump. My original sump pump drain line is broken under my driveway (long story). I need some suggestions on what to construct the well with, and how deep it should be, etc.

I will be running 1 1/2" PVC from the pump, through the basement wall, gluing in a "T" with a elbow above grade, finally expanding to 3" PVC for about 50' to the well.

I'm looking at running the pipe out of the wall approx 18" below grade, and continue to drop the run 1" or so every 5'. I will be renting a trencher to get the job done faster!

For the well, I was considering buying a 32 gallon garbage can and drilling multiple 1/2" holes through the bottom and sides. I would wrap the can with landscapers fabric to keep out any roots, and have the 3" PVC run into the can about 3/4 the way up from the bottom. I'm not sure what to fill the can with (peet gravel?). I would then backfill the hole with the gravel and sand from my yard. By the way, the soil in my lot is mostly sand and gravel so I have excellent drainage. I'm not sure what to do for a cover. I'm thinking that wrapping the fabric over the top and topping with soil would be OK.

The other thought I had was to dig a hole and wrap 4" perforated flexable drain pipe in a coil. Back fill the hole with gravel as I coil the pipe. I seen at Home Depot 3" PVC to 4" adapters.

What do you think? I'm in SE Michigan, so I'm a little concerned about frost/freezing. Is 18" deep enough? What about the gravel - is there something better than peet gravel for this purpose?

They make actuall liners for drywells. I would not use a garbage can. I don't think it is strong enough to not collapse under the weight of the dirt.
http://www.thenaturalhome.com/drywellinstallation.htm
<img src="http://www.thenaturalhome.com/drywell21.jpg"/img>

joed...thanks for the reply. I don't want to sound like a cheap skate but $130 for a plastic tank! WOW!

They recommend the container remain empty with stone/gravel packed around the outside perimeter.

I would think a garbage can would be robust enough with gravel packed inside. Yes?

Hello. I'm about to install the same set-up as you, and I'm also in SE Michigan. I was wondering about your use of the T and elbow above grade....Is the elbow there as a relief port if the below grade drain freezes up, there spilling on the ground? I was unsure about how to plumb it for a possible freeze or blockage.
Also, a neighbor of mine used a 55 gallon open top (without lid) heavy plastic drum, drilled MANY holes (1/2") in it, then filled it with round stones about 3/4" to 1 1/2" dia. . He didn't wrap the barrel with fabric, although I might. He did cover the top of the barrel with multiplr layers of heavy mil black poly film.
The hole was about 10" bigger all around then the barrel, and it was filled with pea stone. He has never had a problem with it, and although most likely against code, he discharges wash machine grey water into it as well as the sump pump. The drums are easy to find for free...Keep your eyes open around carwashes, or small factories. A polite request sometimes results in more barrels than you can use! My neighbor's drywell has been installed for 8 years without a freeze-up or problem.
***added note***
I'm thinking there could be a increased chance of freezing if the elbow you describe is open to the air...That may let cold air into drain line...Anyone elso have any thoughts on this to help us out?

I contacted a friend of mine that does excavation and sewers for his advice. He actually offered to build it for us for the price of materials and the fuel for his equipment!!! He also stated he has made drywells for washing machine gray water, and I might splice my washer output in the same line to save my septic.

The "T" is simply a relief for freezing. I believe that's code (or so I was told). He also stated that the output from the house must exit above grade (through the bond & brick), and enter the drain pipe in a loose connection. This is done so the house can settle and not break the drain pipe. My guy is supposed to start digging for me the next week or so. I post back what we end up doing.

Solar1 - what city are you located?

Here is a link to a dry well design that is similar to what I used. Other than plumbing, all that remains to do is to excavate a large-enough hole and fill it with hardwood mulch.

http://www.oasisdesign.net/greywater/buildersguide/index.htm

Hope this helps.