Sizing a septic tank

[Whitesoulpat]

We want to park our 5th wheel for a few months. We don’t have access to a septic tank and want to install one. How do you size a septic tank? We have 2 black tanks, one is serviced weekly, the other not as much. 2 grey tanks get more use. I don’t want to risk undersizing.

[FleetMan]

If you are considering either a large in ground holding tank or a complete in ground septic system, I’d suggest you contact a local septic tank servicing company for information.

[Winemaker2]

Most local codes will spec size based on number of people the accommodations will house or strictly on # BRs. A typical 2 BR house with max of 4 occupants should be adequate.
Reqmts will vary by state codes but a current "typical" min size septic tank will be 1,000 gal. What is reqd for drain field will be very locale specific and likely require a percolating test to properly design the drainage field.

[Goodspike]

I think you're likely in for a huge expense. Presumably your local government will have some say in what you can put in.

I'm going to make the reasonable assumption that you own the land. I would put something in that would service a future house that you or a future owner might want to build. So that means something that will service at least a 3 or 4 bedroom house in a location that makes sense for a likely location where a house might be built. That way you'll get some return on your investment when you sell.

Also, I'm not sure how big your tanks are, but dumping large quantities into a gravity system is not the best for the longevity of the system. A multi-tank pumped system would probably be best for that use, but it will likely cost more money. And it will require electricity.

[Kenny Loney]

I don't know what area you are in, but in our area septic tanks, actually septic systems are under the jurisdiction of the public health unit. Size of dwelling unit, bedroom#s, fixtures dictates the size of the tank, and then the size and type of leaching bed, type of soil. Also proximity to wells, streams lakes.
Now if you are just interested in a large sealed holding tank, different story. But even here, you would have show the health unit with a signed contract with a licensed septic pumping service.

Ken

[Old-Biscuit]

Originally Posted by Goodspike

I think you're likely in for a huge expense. Presumably your local government will have some say in what you can put in.

I'm going to make the reasonable assumption that you own the land. I would put something in that would service a future house that you or a future owner might want to build. So that means something that will service at least a 3 or 4 bedroom house in a location that makes sense for a likely location where a house might be built. That way you'll get some return on your investment when you sell.

Also, I'm not sure how big your tanks are, but dumping large quantities into a gravity system is not the best for the longevity of the system. A multi-tank pumped system would probably be best for that use, but it will likely cost more money. And it will require electricity.

Keep hearing that 'dumping' cautionary tale
CG Septic systems handle multiple dumps...gravity systems
Our 1500 gallon septic tank at S&B handles me dumping 128 gallons
Been dumping RV waste tanks into S&B septic tanks at numerous places over many years of RV and have yet to encounter issues

Yes...guess you could 'push' some effluent out into leach field/leach pit and cause some clogging
I must be lucky....cause it has never happened


OP.......
1000 gallon minimum if you are going to go thru the legal hoops
Parking 5vr for a few months.....permitting/contracting/installing could take few months

Is this really rural or could you just have a Honey Wagon come dump you as needed

[Goodspike]

Originally Posted by Kenny Loney

Now if you are just interested in a large sealed holding tank, different story. But even here, you would have show the health unit with a signed contract with a licensed septic pumping service.

Ken

That might be a better (cheaper) way to go if the property is not developable later. Holding tanks are basically what our state parks do for their dump stations. I know a small local school that does that for one of their remote buildings. I'd price out pumping services before buying because I would suspect that pumping 1,500 gallons doesn't cost 1.5 times as much as 1,000 gallons, so you might save money over the long run going bigger.

[grindstone01]

Ideas for if you are a DIYS person!

We full time and set up a home made septic system in our son's 5 acres in Mich and also my brothers 5 acres in Texas. Both places we would stay for 2-3 months taking daily showers, using our washer/dryer, and we never had any drainage issues. We always left both of our drain valves open.
For our homemade septic system, I buried 2-5 gallon pails taped together upright and cut a hole in the top 1/3 with a 10', 4" perforated drain tile buried 6" under the sod. The top of the pail setup had a regular threaded 4" pipe opening like used in campgrounds.
Attached is a similar home made septic system only I used a one pail holding tank (could use 1 drum)
https://www.wikihow.com/Construct-a-Small-Septic-System

[twinboat]

I just built a septic tank for my RV.

I drilled 40 holes in each of 2 55 gallon barrels, used 2 inch PVC and a tee into each one.

I dug a hole deep enough to lay them down 8 to 10 inches under the ground, ran a pipe over to the corner of my shed and buryed everything.

[grindstone01]

Originally Posted by twinboat

I just built a septic tank for my RV.

I drilled 40 holes in each of 2 55 gallon barrels, used 2 inch PVC and a tee into each one.

I dug a hole deep enough to lay them down 8 to 10 inches under the ground, ran a pipe over to the corner of my shed and buryed everything.

Did you put in a overflow drain field line? The idea of having a leak proof tank is that water will stay in the tank during non use periods and allow the bacteria to live and continue to decay any solid matter. If you have holes in the bottom of your tank, the tank will dry out, crust over, and plug up the holes for next time's usage.
Time will tell, give us a shout back in a couple of years. A drain line can always be added later.

[aether_one]

Originally Posted by grindstone01

Ideas for if you are a DIYS person!

We full time and set up a home made septic system in our son's 5 acres in Mich and also my brothers 5 acres in Texas. Both places we would stay for 2-3 months taking daily showers, using our washer/dryer, and we never had any drainage issues. We always left both of our drain valves open.
For our homemade septic system, I buried 2-5 gallon pails taped together upright and cut a hole in the top 1/3 with a 10', 4" perforated drain tile buried 6" under the sod. The top of the pail setup had a regular threaded 4" pipe opening like used in campgrounds.
Attached is a similar home made septic system only I used a one pail holding tank (could use 1 drum)
https://www.wikihow.com/Construct-a-Small-Septic-System

"5 gallon" pails? Do you mean 55 gallon drums?

[grindstone01]

Originally Posted by tfryman

"5 gallon" pails? Do you mean 55 gallon drums?

NOPE, 2 - 5 gallon pails with the openings duct taped together work just fine. The drain field does the work by getting rid of the excess liquid, the pails just catch and hold back the solids for the slower dissolving process. Another thing is I left the RV drain valves open all the time, so the 10 gallon holding tank never got overwhelmed. If I were to do a full RV waste tank dump, then I would have needed a larger holding tank.
This worked just fine for 2 adults full timing, taking 2 daily showers, washing dishes, and doing a load of laundry every other day on average.

[twinboat]

Originally Posted by grindstone01

Did you put in a overflow drain field line? The idea of having a leak proof tank is that water will stay in the tank during non use periods and allow the bacteria to live and continue to decay any solid matter. If you have holes in the bottom of your tank, the tank will dry out, crust over, and plug up the holes for next time's usage.
Time will tell, give us a shout back in a couple of years. A drain line can always be added later.

I see your point but I live on a river, with a high water table, so the barrels are in water.

If I didn't have holes, they would pop out of the ground in the spring.

They are building a new house a few lots down. Their 1000 gallon plastic septic tank floated up, wrecking all of the plumbing. Nobody thought to fill it.