Winterizing Septic Tank, seasonal cabin

[archerystud]

Here is my scenario. I have a seasonal lake cabin with a holding tank which I close up usually in Sept/Oct. I drain the lines, antifreeze etc. After talking with some neighbors there seems to be a great debate in what to do with a seasonal cabin for the winter.

I've heard two options: Have the tank completely drained when you leave OR leave it about half full.

To drain the tank makes sense since then there wouldn't be anything inside to freeze and crack the tank from the inside. However, since I have a level lot, I'm sure that any ground water could also freeze and push in on the tank from the sides.

So what do you do to winterize your septic tank?

[delcecchi]

Holding tank or Septic with drainfield?

[BAIT956]

I have the same situation, with a holding tank.

Heeding advice from several respected septic services, every fall, I drain both sides ( it is a 2 section tank, 800 gallons per side) down to around a quarter to a third full or less, leaving plenty of room for expansion. This also provides enough weight and stability against outside pressures.

Never have had any problem.

[Nutty Fisherman]

If you have clay ground I would not pump your tank. If you pump your tank and the ground freezes it will push the tank in. When you leave it full it will freeze equal. I would cover it with some bales of straw, or bags of leaves.

[archerystud]

Thanks for the replys.

I have a 2 section 1600 gallon holding tank now and my ground is clay. Would it do any good to cover the ground if the tank isn't being used for about 7 months out of the year? I could see it helping if you had bacteria working in there but in my case I was wondering if it would do any good.

I wonder what the maker of a septic tank actually recommends?