max slope or length to new septic tank

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    • #279584
      MasterPlumbers
      Keymaster

      I am in installing a new septic system. It is about 200 ft from the home and has a pretty steep slope (steep driveway). Is there a maximum slope to a septic tank, beyond which will cause solids from liquid separation.
      Are the clean outs every 60′ or 100.

      thank you Carl

    • #301727
      Retired plbg1

      You should give the sewer about 1/4″ to the ft. or 1″ to evey 10′. You should have a co. evrry 100′.

      Art Retired Plbg.

    • #301757
      digger

      Carl,

      The fall is not important, the flush capacity is the important matter, the flush should be not less than about 2 gallons then the solids will not seperate from the water.

      Digger

    • #301759
      siekster

      The earlier post was correct… fall should be between 1/4 to 1/8 of an inch. The number of cleanouts will generally depend on the local or state codes, anywhere between every 50 to 100′, or after a certain number of turns, for example, every 4 45’s.

      Flushing capacity for a standard residential toilet in the US is 1.6 gallons per flush, which is plenty. For a sewer line that long, proper grading will be the key to it properly draining.

    • #301760
      digger

      Siekster

      The falls for drainage lines in NSW Australia are

      65mm pipe =   1 foot fall in 40 feet

      80mm pipe =   1 foot fall in 60 feet

      100mm pipe =   1 foot fall in 60 feet

      125mm pine =   1 foot fall in 80 feet

      Regards

      Diggerdigger2007-12-01 13:23:55

    • #301761
      siekster

      Hey Digger!

      I had to pull out the old mm to inch calculator for that one!! Here in North Carolina, we use the “International” Plumbing code, although it seems to vary from state to state, let alone internationally.

      Drainage lines 2″ and under- minimum 1/4″ per foot, or 10″ fall for 40 ft.

      Drainage lines 3″ to 8″- minimum 1/8″ per foot, or 10″ fall for 80 ft.

      Drainage lines 8″ and above- minimum 1/16″ per foot or 10″ per 160 ft

      More pitch allows more DFU’s (Drainage Fixture Units) to be placed on drainage lines, up to 1/2″ per foot fall.

      Siekstersiekster2007-12-02 15:33:21

    • #301918
      Bxbyard
      carl dearth wrote:
      I am in installing a new septic system. It is about 200 ft from the home and has a pretty steep slope (steep driveway). Is there a maximum slope to a septic tank, beyond which will cause solids from liquid separation.Are the clean outs every 60′ or 100.

      thank you Carl

    • #301919
      Bxbyard

      I want to be convinced slope cannot be too much! keep being told solids will seperate so best to install steps ( not sure if 90 deg or 45 deg steps would be best if required)… iread sufficient flush volume is one solution but if flush is modest will too much slope make solids separate??..any expert/ prectical advice apprecieted

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