[logan176]

I'm in the middle of a garage renovation and driveway install. I just laid drainage pipe to connect a downspout to a dry well. Originally, I was going to use a 55 gallon drum, but I'm not sure where to get one locally.

Home Depot has this:
NDS 24 in. Plastic Storm Water Leaching System-FWAS24 at The Home Depot

When I asked a local drainage supply company, they only had huge drywells. They instead recommended a biodiffuser:
makewaysepticsolutions.com

The biodiffuser is technically designed for sewage but hit holds 120 gallons when the other container holds 55 gallons. Is one of these products going to work better than the other?

[ma0641]

One good rain for only a short period will easily fill either one. The bio chamber is designed for low flow sewerage wastes-that's what I have at my house. Unless you are on sandy soil I don't think either one will work due to water volume.

[logan176]

I had a feeling the BioDiffuser might not work for the same reason you described. When I called back the drainage supply store, I spoke to a different person who suggested a Flotec Recharger. I was told that it holds 189 gallons and that would be fine for the 400 square feet of roof that it needs to drain. I haven't been able to find any info on this product. Any thoughts?

[logan176]

I think he was talking about this:

Information on CULTEC Stormwater Chambers

[ma0641]

I had a feeling the BioDiffuser might not work for the same reason you described. When I called back the drainage supply store, I spoke to a different person who suggested a Flotec Recharger. I was told that it holds 189 gallons and that would be fine for the 400 square feet of roof that it needs to drain. I haven't been able to find any info on this product. Any thoughts?

Never heard of it. Only know them for pumps and bladder tanks.

[smearcase]

I had a problem area where two down spouts had been put underground into a 4 " pvc by the previous owner. When I finally tracked it down and excavated I found that they had installed about 15 feet of the 4" pvc and just deadened it against the soil at about 18 inches deep, no protection at all on the end of the pipe and no perforated pipe.
I extended that pipe with 20 feet of 6 inch pipe (had to drill to perforate it myself) and laid it on 6+ inches of #57 stone (about the size of a golf ball), and at about a 1/4" per foot grade.
That was two years ago and it had held up in at least 3 terrific storms (1 to 3 inches per hour type storms). I could have turned up the end of the pipe and "daylighted" it to allow it to bleed off and run on the surface, which I may do at some point but no need based on how it has performed so far. If my math is correct, my pipe will only hold about 30 gallons of water but with the perforated pipe and stone, it dissipates fast enough to prevent a backup. And I do not have a sandy soil by any means. The first RT backhoe we tried to use couldn't dig it. We got a track hoe which worked but repair to the lawn was the only problem encountered for the project.
I wanted to just run the pipe until it came out of the ground but my yard is too flat. If you have some decent slopes away from your house you may be able to install a pipe to a point where it can just outlet onto the surface of the existing ground.
I have some other problem downspouts which I hope to connect into that same system and I have little doubt about it being able to handle large storms. Especially if I turn up the low end to let it flow on the surface, if it starts to backup.

[logan176]

I thought about doing it that way but the first 16 feet will be under my new driveway that will be installed on Thursday. I used solid PVC because I was worried that the seepage from the perforated pipe would weaken the soil under the driveway.

As of right now, the pipe that exits the other side of the driveway is 2 feet below ground. I can use the perforated pipe at this point, but I don't feel comfortable just capping the pipe and my yard is too flat for an above ground outlet.

[logan176]

Smearcase, using your example I would probably have to dig another 40 feet of trench. I'm not sure what's the tougher dig, that or the dry well. However, I will keep what everyone has told me under advisement.

[logan176]

Just to give some more info, below is a photo of the area to the left of my driveway where I am considering putting the dry well. As you can see, it is about 10'-15' away from a Japanese Maple and about 3 feet away from my 1-car garage. The garage does not have a foundation, it's on a slab with thicker concrete around perimeter.

I guess another option would be to take my neighbor's 55 gallon drum, which I was just told this morning he can get from work, and connect it to the PVC under the driveway. Then connect the drum to a 4 inch corrugated drainage pipe that would lead under the gate and into the backyard.

Any thoughts?

[smearcase]

Don't forget how high your gutter and down spout are located with respect to where the end of your pipe would be. An outlet, even if it is at ground level will still drain with water seeking its own level, but if you can't use perforated pipe at some point, the pipe would lay full of water. But maybe you can use a perforated pipe in the option you mentioned.
The highway agency I worked for allowed rainleaders as they called them, to drain into the street or in some cases into a road inlet. When we installed new curb and gutter, we would (and were required to) bring usually a 4 inch pvc through the curb and end it at the curb face. Any possibilities there if the local jurisdiction could allow something along those lines?
Could you go under that back gate and do some perforated (and the holes are located near the bottom of the pipe, at about 45 deg. Or less leaving some flowline, not top just to clarify) pipe assuming that would not be near the house foundation? Stone under the pipe will significantly increase the capacity of the system to work.

[logan176]

Smearcase, your idea of digging a 40' trench and using perforated pipe is starting to better and better. Especially since I can rent a Ditch Witch to do most of the digging for me. The Ditch Witch diggs a trench that is 36" deep and 5" wide. The depth will be enough for me to lay 6" of gravel and still have the proper pitch.

Do you think the 5" width will be enough if I use 4" perforated pipe?

[teenerds]

Hey Logan,

I found your post a few years back on making your garage 2 ft taller. Did you ever go through with that? We currently have an 8ft tall garage and would like to add 3-4 ft.

[logan176]

I decided not to because I wasn't sure why the floor was cracking. But this project showed me that the garage had no foundation when I thought it did. If I made the garage taller it probably would have collapsed.

Hey Logan,

I found your post a few years back on making your garage 2 ft taller. Did you ever go through with that? We currently have an 8ft tall garage and would like to add 3-4 ft.