Does larger tank mean larger field?

[Hamilton010263]

We are in the process of planning a home on a property we currently live on. In 1996, the existing home was built with an 800 gal tank and apx. 270' of drainage in the field. The county is saying we must upsize the tank to 1250 to meet current standards.

My question is, if there is no increase in the amount of bedrooms, people, or water usage, is there a reason to enlarge the field for the larger tank? My understanding is that the only thing that flows out into the field is whatever the tank won't hold and unless there is more water being used, that outflow should remain the same regardless of the tank size.

Can anyone explain this to me?

 

[johnjh2o]

The purpose of the tank is to separate the solids from the liquids preventing the solids from entering the drain field and plugging them. The size of the drain field is determined by the soil conditions and the number of bedrooms in the home. I would say your drain fields should be fine as long as there have been no problems with them. But it's up to the county to make that decision.

 

[Zanne]

Hamilton, you need to contact someone from the Department of Health to get a permit for the installation of the tank. Where I live, this is free. When you get the permit it should specify the length required for the field line. The inspector will likely have you do a percolation test to determine how much field line is needed. The inspector should give you instructions on what to do.
I was required to dig four holes at least 4" in diameter and at least 24" deep and fill them with water the day before the inspector came out. I was instructed to leave 5 gallon buckets of water next to each hole (or have a hose able to reach them). The holes had to be a certain distance apart-- I think 30' each. The holes were in the general area of where the lines would be placed.
When the inspector gives the length, make sure he/she specifies what type of field line is being put in. My inspector recommended 330ft of standard pipe in gravel. After further correspondence he informed me that my state allows for an infiltrator system that reduced the length required by 40% so I only need 198ft (but since it comes in 4' lengths it is 200ft-- so two 100' field lines). Field lines are not allowed to be over 100' each and the change in depth (because field lines are put in at a slight incline to allow water flow) of 12" total. With infiltrator systems they are supposed to be level but can incline about an inch, IIRC.

Your area may have different requirements. Not all of the infiltrator systems are approved for all areas, so make sure you talk to the Dept. of Health inspector about what is allowed. Also, the office should provide you with a list of licensed septic tank installers that you can research and call to get quotes. They will want to know what the permit specified in terms of field line length and what size tank was recommended.

Before the new system is finalized, the old septic tank will need to be drained completely and either filled in or removed.

Good luck!

(I'm still waiting to hear back from someone from my local Dept of Health so that I can find out if my installer has the green light to install today or if we have to reschedule again due to inability to schedule the health inspector to come out on the day of inspection).