Septic tank install

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turbokp43

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I am building a barnament, a barn with an apartment, for my family to live in while we build a new house. I am doing everything myself, some this I have never done before. I am going to be installing my first ever septic tank. I have a 500 gallon low profile poly tank. My understanding is that I will want the main drain coming into the tank to be no more than a quarter inch per foot of fall. Do I gravel the drain line coming in? If so about how much gravel should I put around it? Then do I gravel around the tank? How much do I put around it? My research has indicated that I believe it needs to be compacted as well? Then I need to fill the tank with water as I fill around it. Do I have all this correct?
 

Twowaxhack

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1/4” per ft is correct for the incoming sewer. It’s compacted a little but not much.

We don’t put gravel around the tank or incoming sewer pipe in my area.
 

JG plumbing

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Gravel under the pipe compacted tight. Then pipe. Then gravel over the pipe about 8"above the pipe, then compact. Then dirt for the rest of the fill.

You can use what you want to fill around the tank, but yes it should be compacted. Whatever equipment you use to compact shouldn't be too heavy. Since your tank is plastic I think filling it is a good idea.
 

PerplexedPlumber

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Fines are used for bedding in our area for two reasons:
1) There is more rock than soil, and this provides a buffer zone to keep rocks from working into the pipe, causing a leak.
2) If you or someone else needs to dig again later, there is a warning point showing that pipe is buried. The excavation people are tuned in to the white appearance of the fines.
 

JG plumbing

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Oh yeah. If this is a long run bury a tracer wire with the pipe. You'll thank yourself later.
 

turbokp43

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Fines are used for bedding in our area for two reasons:
1) There is more rock than soil, and this provides a buffer zone to keep rocks from working into the pipe, causing a leak.
2) If you or someone else needs to dig again later, there is a warning point showing that pipe is buried. The excavation people are tuned in to the white appearance of the fines.
What are fines?
 

PerplexedPlumber

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In areas where limestone gravel is produced, the fraction of gravel that is approximately 1/4" or less (sometimes a little larger) is considered "fines".

The tracer wire that JG mentioned would allow the companies that assess a site before digging is done to locate the lines, so would be good in any case.
 

JG plumbing

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A single 12 or 10 gauge insulated wire. Tracer wire is usually sold as tracer wire and has blue insulation. I usually duct tape it to the top of the center of the pipe before burial. They have terminals you can buy, but just running the wire vertically up out of the ground on either or both ends is fine for termination. Then when it (the pipe) needs to be found a locator can clip onto the wire.
 

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Are you in a rural area? Or do you have code to go by.500 gallon tank is small. In my state Tank size goes by bedroom 1000 gallon 2 bedroom 1250 gallon for three bedroom and 1500 for 4 bedroom. You didn't mention what kind of leachfield you are installing. There are videos on youtube showing homeowners and contractors installing systems .I like pipe and stone or cement chambers the best infiltrators are good they are plastic chambers Enviro tubes can be problematic .Venting leachfields helps them to last longer.Water softeners if required for well water shouldn't be hooked into septic they should have their own drywell if legal .A cover and riser on your tank would make servicing it easier for your pumper.
 

turbokp43

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Are you in a rural area? Or do you have code to go by.500 gallon tank is small. In my state Tank size goes by bedroom 1000 gallon 2 bedroom 1250 gallon for three bedroom and 1500 for 4 bedroom. You didn't mention what kind of leachfield you are installing. There are videos on youtube showing homeowners and contractors installing systems .I like pipe and stone or cement chambers the best infiltrators are good they are plastic chambers Enviro tubes can be problematic .Venting leachfields helps them to last longer.Water softeners if required for well water shouldn't be hooked into septic they should have their own drywell if legal .A cover and riser on your tank would make servicing it easier for your pumper.
We are in rural area with no code for the septic tank, it is a bit small, but this is for a temporary apartment in a barn/shop until we build our home.
 

turbokp43

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Since someone asked about the leach field, I have questions about that too. How do I know how many laterals I need? How long should they be? I am not getting the perk test done to cut down on costs. My research leads me to believe that I need to dig the trenches 18-36 inches wide and up to 36 inches deep. I then place at least 8 inches of gravel, then the pipe, then more gravel, some sort of fabric to keep the dirt out and then dirt. Is the pipe the think wall pipe or should I just drill holes in regular pvc? How big are the holes? There are a lot of opinions of what slope to put the pipe on some say 1/4 per 8 ft. some say less some say more. What is the consensus. If I'm putting the leach field on a hill how do I run the laterals? Across the slope? Does anyone have a better plan for a leach field, keeping in mind I need the most economic option because this is not a permanent situation.
 

JG plumbing

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You called the county health department and they said they wouldn't inspect it or tell you how they would like to see it built?
 

JG plumbing

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In our area we don't dig trenches we dig a long rectangular hole at certain a depth below the leach field. Then we fill the hole with layers of sand and gravel and filter fabric. The leach field size depends on the tank size which depends on the household size. I believe this is the actual correct way to do a leach field which is up to date with current engineering standards.
 

JG plumbing

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The county says that since I have over 25 acres they don't care what I do.
You better be very careful with that horrible thought. The EPA would definitely care and can come in any time with unforseen motivations, and force something they consider compliant.
 
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