Need some sewer line help

[Freds]

It looks like I can put my backhoe to good use again. I'm getting my driveway concreted and want to put a sewer line across it for future use. The township supervisor/planner said to come out the cellar wall at the same height my septic line comes out (which comes out a different wall). That would put the future sewer at about 2' below grade at the house. Here's my dilemma, the ground falls away towards the driveway about 2' in 15', then it's level where the driveway is, then falls another foot where I would like to end and cap the line. That's a pretty steep pitch. Around here we run sewer at 1/4" fall in 4' so the liquid doesn't run away from the solids. I'm not sure what kind of pitch to run at, follow the natural grade where it leaves the house, or dig down deeper to try to get a shallower pitch.
I should also mention that I will be crossing an underground electric and phone line. If I stay 2' below grade I will be above it, so even if I am deeper at the house, I should still be above it running a shallower pitch.
And another concern that crossed my mind is if I run at the steeper pitch, won't that mess with me trying to elbow up inside the house and be plumb? Do you use a fernco ftg there to allow some flex so your vertical drop can be ran plumb?

Lots of questions, I know. But I know where to go for sound advice. So what do the plumbers here think?

Thanks

 

[DaveOmak]

Freds, Mornin'. You going to city sewer or a septic tank?
Around here, you put your septic tank close to the house. 15 feet or so. Then the clean water can run to the drain field where ever it has to. Even using a sump and pump to run it uphill.
City sewer is a different deal. The city will tell you how to do that. Dave

 

[Freds]

Mornin' Dave.
The "city" said to run the pipe out of my basement at the same height the septic was at, then get it across the driveway. I believe my situation is a lot more relaxed than what you might think.
It is for future sewer that is supposed to be going in within the next five years so I don't have to tear up my driveway, which is being poured the end of this week.

 

[Damifino]

I would maintain your 1/4", then use 45's to step down your sewer line as needed, you made need to do several times to your capping off point.

hth

 

[EddieWalker]

If my memory is right, you can have your sewer lines range from 3 to 8 degrees of slope. While too much angle is said to cause the fluids and solids to seperate, that's based more on the older clay pipes than modern PVC pipe. I wouldn't worry about going a bit steeper on your slope if it wasn't too rediculous.

Using 45's and 22.5's to drop down quicker will also work, just be sure to use Schedul 40 for all of it, including the pipe. I don't think the cost savings is worth it to use thin wall drain pipe.

Once you get your pipe past the house, put in two sweeping T's that will allow you to access and snake out the drain lines. The T's go in so that they angle towards each other so if you don't have any dead areas that you cannot get to.

Eddie

 

[Pops15]

1/4" in 4' is the correct fall.
Have they done the engineering work for the future sewer? How do you know how deep it will be? I'd be very hesitant to run the line from the house without knowing how deep the main will be.

Once the sewer main is installed why don't you just cut the line going to your septic and tie it to the main? That's how it's usually done.

 

[Freds]

I appreciate all the input.
The 45's to tier down was a great idea. I was thinking the pipe should be a straight section. Which might be preferred, but not necessary.
Thanks for the PVC vs clay advice and the range of pitch Eddie.
Pops, the main at the road will be 8-1/2' deep. I don't want to tie in to the existing septic line outside because I can't get my tractor into that area without having to take down fencing, and it would mean a lot more trenching outside following alongside the house fairly close. It would be a trickier dig as I'd have to angle the tractor in.
And I'd just as soon have all new pipe anyway. I don't like the way any of these drains were run in the house and the toilet currently raises before it drops. Running all new will let me run them the way they should be run.

 

[Hillfarmer]

You do not have to worry to much about the pipe being too steep. What one flush leaves behind the next must move. You do want the pipe to be as straight as possible or else in the future when a clog does occur you will most likely end up digging. There are very few sewer cleaning heads on the market that will go around a 4" PVC bend. A snake or eel will go around the bend but are less effective than a high pressure cleaner.

Most utilities will require gasketed SDR 35 pipe for your lateral. Be sure to lubricate the gaskets with pipe lube or dish soap. I would recommend putting the pipe inside of a casing under the drive way and sealing both ends of the casing with a boot. Just incase you need access in the future.

 

[Ranger Rick]

Question for you. Are the septic fields in the area beginning to faiil? Is that why the city is planning a sewer line. You might want to keep your septic if you can because the city will charge an arm and a leg for the privilege of hooking up to their sewer line and the rates just continue to go up. Just trying to save you some time and money.

 

[Freds]

I don't know about that SDR pipe, HF. The township just said 4" sch 40.

It's not an arguable situation Rick. When they come by with the main, you are required to hookup. Working septic or not. There are a few townships around that tried to band together and fight it, but couldn't. It's an EPA thing.