[NA] Plumbing info; sewage

Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
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Dave Taylor
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I am looking at putting in a small m.i.l home near my guest room/garage and adding the drain line from the home to that which the guest room uses. The 600sf guest room has its own septic system (tank and 'cave')
I am trying to do some rough initial planning on where to put the home to accommodate the utilities; at this point, the drain line. (All detailed planning and design will be done by those skilled at it.)
Please:
a) ignore administrative items like inspections/code; that is not the reason for this thread.
b) ignore capacity concerns; that will be covered by plumber, and is not a part of this thread.

I am finding the optimal slope is 1/8" to 1/4" per foot - correct?
I cannot find how long can the run from building to tank be? Is there a practical or coded limit? I don't think 50' is too long. Is 150' too long? Where to look up?
Is there a minimum depth the pipe needs to be?

A description of the plan view would be:
-guest room septic discharge is about 40' from the tank.
-initial thoughts on new home location is 100-150' from the tank.
-guest room and tank might be 100' apart; so you could draw an unequal triangle if you were to join the three on paper (guest, home, tank) and within the triangle is driving surface.
-leach field will not interfere with proposed home location.
-new home is slightly uphill from tank.

Plumber will be consulted before proceeding; certainly before any dirt is turned.
 
Minimum slopes for sewer service laterals are normally covered by local codes, which is governed by minimum transport velocity plus some margin, and it's usually 2%, or about 1/4 inch per foot. 150 feet should not be an issue. Plan on running some main line with a cleanout, and joining the main line to the drains by wye connections.
 
I built something similar for my detached shop/loft which is about 150 ft from the main house, driveway/turnaround between them. The septic treatment unit is offset but between them (triangle).

1:100 slope (1/8 inch per foot) is the absolute minimum for 4 inch or smaller pipe. You may be able to use less slope on larger than 4 inch but it is not recommended.

I used 4 inch ABS pipe and mechanically protected it under the driveway segment with a steel pipe casing over it.
1:50 slope throughout (1/4 inch per foot), bedded the line in clean sand before covering with the native clay backfill
I worked the slope back from the tank connection point to the vertical stack in the building, the intersection determines the depth of the stack below the floor; in my case I had plenty of natural elevation grade rise to the building from the tank to work with.
Total length of line from the loft bathroom to septic plant is about 105 feet.
I have one x 90 degree horizontal turn near the end of the run, to line it up to enter the tank, and used 2 x 45 deg ells with a 6 inch pipe section in between them - try to avoid using single 90 deg ells for horizontal turns or turns from vertical to horizontal (e.g. bottom of stack to the drain line).
In addition to the "Y" clean-out on the stack just above the floor in the building I installed a "Y" clean-out just upstream of the first 45 deg ell on the horizontal turn described above; 4 inch pipe to surface with a screw on cap that stands about a foot above the grade in the grass. Have never had to use it, but seemed cheap insurance during the installation.
Depth of burial - You don't have the frost issues I have so your depth will be governed by soil conditions and local codes, but I would probably use 3 ft minimum as a guide.
System has been in service since 2009 with absolutely no issues so far.
 
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First rule of being a Plummer : **** runs down hill
 
Here in Massachusettstan, you need to have the system designed by a civil engineer. Plumbers usually don't install the system, we have contractors, usually excavation types who do this. The designer designs the system based on the number of bedrooms which dictates the flow to the tank and the type of soil in which the effluent will flow. Lot size dictates the max. size limit of the system. Assuming your guest room septic is designed for that specific application you would be SOL adding another structure to it. But this is Massachusettstan, New Hampshire is similar, don't know what they do in Texas.
 
while yer at it....put in a clean out at the septic tank....and as far upstream as possible.

You'll thank yourself if you ever get a stoppage. That extra cleanout will speed things up and prevent re-digging up the works.
 
Of course you could dig a trench to the pipe in your system, add a 45 fitting, run a pipe to your MIL room, cover it over and no one would probably be the wiser and it would probably work fine. They would probably figure it out when you sold.......
 
You don't need a grinder if the pumps are after the septic tank, simple effluent pumps will work ... you're only supposed to have liquids going to the field. I lived with such a system for 25 years or so. Replaced the pumps twice. We had an alarm that let you know the level in the pump chamber got to high which I referred to as the "deep s--t" alarm.
 
flyingron said:
You don't need a grinder if the pumps are after the septic tank, simple effluent pumps will work ... you're only supposed to have liquids going to the field. I lived with such a system for 25 years or so. Replaced the pumps twice. We had an alarm that let you know the level in the pump chamber got to high which I referred to as the "deep s--t" alarm.
Click to expand...

For that matter, you could use standard solids handling lift pumps and a manhole EQ tank before the septic, but a grinder pump and small diameter HDPE pipe will be a whole lot cheaper. Whether local codes will allow them might be another matter though.
 
[QUOTE="PaulS, post: 2201906, member: 2569"They would probably figure it out when you sold.......[/QUOTE]

Whole thing (new home and septic attachment) is probably coming out before then.
 
flyingron said:
You don't need a grinder if the pumps are after the septic tank, simple effluent pumps will work ... you're only supposed to have liquids going to the field. I lived with such a system for 25 years or so. Replaced the pumps twice. We had an alarm that let you know the level in the pump chamber got to high which I referred to as the "deep s--t" alarm.
Click to expand...

Of course if the alarm float fails by filling up with **** the alarm doesn't go off. You end up with a natural alarm, loud strange gurgling noises, toilets filling and emptying on their own. If you are lucky this will happen before the fountain in the bathtub, which is the final warning before your house fills up with ****. Voice of experience here, fortunately we figured it out during the strange gurgling stage and it didn't get to the fountain stage.
 
Actually, we had the alarm fail because one of the two pumps tripped the breaker (the alarm is powered by the pump controller and there's no battery backup). Fortunately, there's some head room in the septic tank above the output to the pump chamber so I caught it before we had backup into the house.
 
flyingron said:
Actually, we had the alarm fail because one of the two pumps tripped the breaker (the alarm is powered by the pump controller and there's no battery backup). Fortunately, there's some head room in the septic tank above the output to the pump chamber so I caught it before we had backup into the house.
Click to expand...

Have an effluent pump that has failed twice and an ejector pump that has failed once. Plus the alarm floats, which get replaced with the pump. The first time the alarm float had failed. Doesn't look like a fun job to replace them, but they get paid well.
 
I watched them replaced both time (and yes we do new floats and other things along with the pumps, once you've got the chamber opened up and things pulled up, you might as well do them all).
 
Well, so far no one has answered all your questions and they've ignored your request to refrain from providing replies to things you didn't ask. But at least you know what the requirements are in Massachusetts for an underground plumbing system.

Fall of 1/4" per foot is ideal. A run of 150' will not create any problems, and the initial bury depth of 24" for the line at its exit from the new room perimeter is adequate and meets code.

Your plan is not unreasonable, and should work fine. The most significant restriction is the invert, or depth, of the septic tank inlet. The bury depth of the piping will increase one inch per 4' of horizontal run.

As an example, if the run is 80' and begins at 2' below grade, the end of the run will be 3' 8" below grade. Your septic inlet needs to be no higher than 3' 8" below grade or you will need a lift pump. You can also adjust the fall to 3/16" per foot but that's the shallowest angle I would recommend.

But in general what I've described should work fine for west Texas.
 
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3393RP said:
Well, so far no one has answered all your questions and they've ignored your request to refrain from providing replies to things you didn't ask. But at least you know what the requirements are in Massachusetts for an underground plumbing system.

Fall of 1/4" per foot is ideal. A run of 150' will not create any problems, and the initial bury depth of 24" for the line at its exit from the new room perimeter is adequate and meets code.

Your plan is not unreasonable, and should work fine. The most significant restriction is the invert, or depth, of the septic tank inlet. The bury depth of the piping will increase one inch per 4' of horizontal run.

If the run is 80' and begins at 2' below grade, the end of the run will be 3' 8" below grade. Your septic inlet needs to be no higher than 3' 8" below grade or you will need a lift pump. You can also adjust the fall to 3/16" per foot but that's the shallowest angle I would recommend.

But in general what I've described should work fine for west Texas.
Click to expand...

And New Hampshire, you're welcome.
 
3393RP said:
Well, so far no one has answered all your questions and they've ignored your request to refrain from providing replies to things you didn't ask. But at least you know what the requirements are in Massachusetts for an underground plumbing system.
Click to expand...
Give me a break. It was answered and despite protestations to the contrary, people putting in additional two cents is unavoidable here (and there's nothing you're going to do about it).

Fall of 1/4" per foot is ideal.
Click to expand...
1/4" per foot is ADEQUATE. Contrary to oft-repeated old-plumbers tales, there's nothing magic about this slope. If you have to go steeper, you can fine. Shallower, may cause issues.

nd the initial bury depth of 24" for the line at its exit from the new room perimeter is adequate and meets code.
But in general what I've described should work fine for west Texas.
Click to expand...
Yep and you have NO FROST LINE to speak of in Texas. In New Hampshire where he is, he'll want to keep his lines 12" below the frost line which is going to be deeper than 24"
 
Why the hostility?

I say 1/4" per foot is ideal because it's a good slope that will avoid most blockage issues and it minimizes excavation that a steeper slope would entail. Why dig deeper?

The OP's location information says he's in west Texas, so the frost line in New Hampshire isn't pertinent unless that information is incorrect. I can only go by what it says.

With all your CAPITAL letters I guess you think I insulted your knowledge of ditch digging, if that's the case I don't know how to respond. This isn't a contest.
 
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Also 1/4 inch per foot is typically the minimum per code for 4" service laterals. If you want shallower, go bigger. Trunk mains are usually designed with far shallower slopes, down to about 0.0002 for large diameter lines. (0.2%).
 
I forgot to mention another reason why I think using less than the 1/4"/foot slope might be an issue. With the newer two stage flush lower flow toilets (1.0 and 1.6 gallons per flush) it might cause problems. I haven't seen anything on the internet which mentions this, it's just something I was thinking about after I installed one of these toilets in my house.

A big chuffer might not move downstream as planned with a shallow slope and less water. ;)
 
3393RP said:
A big chuffer might not move downstream as planned with a shallow slope and less water. ;)
Click to expand...

Some things just call for a double flush.

I am trying to understand the need for a water saving toilet on well&septic.
 
I have a rental house with a septic tank. The county has changed the standards for the field absorption and how close the septic can be to the lake that's about a quarter mile from the house. If the tank rolls over and dies, I will be forced to replace it with an aerobic system. Last estimate I got was $8,500.

It would be a big hit on my budget. That keeps me up at night occasionally.
 
forced to replace it
Click to expand...
What are the failure modes, what can be done to keep it going for a long time?
Pump it regularly? The system consists of piping, tank, leachfield, right?
So either it gets over-full and plugs up or a pipe/tank breaks?

Some things just call for a double flush.
Click to expand...
Has a study been done on low volume toilet tanks? With all the double flushing I have seen/heard, I am thinking we are using more water; a paradoxical outcome.
 
3393RP said:
I have a rental house with a septic tank. The county has changed the standards for the field absorption and how close the septic can be to the lake that's about a quarter mile from the house. If the tank rolls over and dies, I will be forced to replace it with an aerobic system. Last estimate I got was $8,500.
Click to expand...

In MD, the last governor by executive fiat decided that all septic systems have to be 'best available technology' (BAT), even those outside of the Chesapeake Bay critical area. Same thing, if something fails on your existing system, you have to get one of those aerobic systems. It's not just the up-front cost, they also have operating expenses for power and servicing. This may get rolled back, but for now people are stuck with stinking expensive aerobic septics.
 
Let'sgoflying! said:
What are the failure modes, what can be done to keep it going for a long time?
Pump it regularly? The system consists of piping, tank, leachfield, right?
So either it gets over-full and plugs up or a pipe/tank breaks?


Has a study been done on low volume toilet tanks? With all the double flushing I have seen/heard, I am thinking we are using more water; a paradoxical outcome.
Click to expand...

Nah, old toilets used to use up to 7 gallons per flush, now they are like 1.6 gallons, so you need to flush it 5 times for one flush of the old 7 gallon toilets toilets. Even the less old toilets averaged 3.6 gallons, so at the end of the day, even with some double flushing you still use half the water. The ones we have work pretty well. It pays to research them if you are getting a new one.
 
Let'sgoflying! said:
What are the failure modes, what can be done to keep it going for a long time?
Pump it regularly? The system consists of piping, tank, leachfield, right?
So either it gets over-full and plugs up or a pipe/tank breaks?
Click to expand...


No, eventually the leach field can plug up with an anerobic biological slime, the soil will no longer percolate, and the bubbling crude starts welling up at the far end.

Just had significant work done on mine to add a new leach field. $$$ :nonod:


Reducing water flow and solids from sources like garbage disposals, leaky toilets and water softeners can help, as well as rotating across multiple fields to let them "rest."
 
ElPaso Pilot said:
No, eventually the leach field can plug up with an anaerobic biological slime, the soil will no longer percolate, and the bubbling crude starts welling up at the far end.
Click to expand...

That's happened once, and thankfully it recovered.

I could dig a new field myself and maybe no one would notice. But it's in a small town, and whoever I hired to haul off the overburden would let it be known what I was doing.

If I followed the rules and used a licensed company they won't work on it.
 
3393RP said:
That's happened once, and thankfully it recovered.

I could dig a new field myself and maybe no one would notice. But it's in a small town, and whoever I hired to haul off the overburden would let it be known what I was doing.

If I followed the rules and used a licensed company they won't work on it.
Click to expand...


I let my old field rest for 2 years to help the biomat decompose, and just turned it back on. We'll keep our fingers crossed and see if it has recovered!!
 
My house in Virginia had two fields and each year the county would remind me to go out and throw the sh-t-switch to change to the other field.
 
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