Looking for what Codes say about ISF systems
#1
07-16-12, 07:22 PM
Looking for what Codes say about ISF systems
At this point, our family is considering replacing the current septic system with an ISF System, but we don't want to spend money on an engineer to tell us how big it needs to be. We need to determine (roughly) what the code requires in terms of 1) Size for the two tanks, 2) Size of the Sand Filter Box, and 3 the Size of the drainfield for a 3 bedroom, 1 1/2 bath home.
The soil is CLAY/VERY POOR, and will definitely fail a Perc Test (don't ask me how it "passed" for the existing septic system), so the ISF system is one of the only ones that I see permissible to the code, in the size space available.
As I understand from what I have read online so far, the ISF can be below ground (unlike a mound filtration system, which has to have a mound that is above "ground level".)
But what I can't seem to find is some basic information on what the building codes require in terms of size.
I know each area is different. In this case, we're located in Lockport NY, but I'm hoping to get a general idea what is required, and i'll overestimate the size by 25% which should determine if it's possible to begin with, before hiring a engineer to actually design one for the house.
Thanks.
Ken L.
Western New York
The soil is CLAY/VERY POOR, and will definitely fail a Perc Test (don't ask me how it "passed" for the existing septic system), so the ISF system is one of the only ones that I see permissible to the code, in the size space available.
As I understand from what I have read online so far, the ISF can be below ground (unlike a mound filtration system, which has to have a mound that is above "ground level".)
But what I can't seem to find is some basic information on what the building codes require in terms of size.
I know each area is different. In this case, we're located in Lockport NY, but I'm hoping to get a general idea what is required, and i'll overestimate the size by 25% which should determine if it's possible to begin with, before hiring a engineer to actually design one for the house.
Thanks.
Ken L.
Western New York
#2
07-16-12, 07:47 PM
Super Moderator
Depends on how much water you use, the size of the home or occupants in the home. All codes are different.
In my town you need to size for 250 gallons per bedroom for tank size for solids The effluent going to a sand bed is roughly @ 300 gallons a day would need a 40x40 field. 400 gal=50x50.
Are you going to use the effluent for irrigation?
But there are many other factors and this is a rough estimate and your codes will vary.
Is there a reason why you want this system? They are expensive. Did they tell you you cant use a traditional system?
In my town you need to size for 250 gallons per bedroom for tank size for solids The effluent going to a sand bed is roughly @ 300 gallons a day would need a 40x40 field. 400 gal=50x50.
Are you going to use the effluent for irrigation?
But there are many other factors and this is a rough estimate and your codes will vary.
Is there a reason why you want this system? They are expensive. Did they tell you you cant use a traditional system?
#3
07-16-12, 11:49 PM
Three reasons..
1) We want to expand the house, and the current septic system is in the way, so there needs to be a new one
2) The soil will not pass a perc-test. I can't explain how it 'passed' the first time, but I know for a fact there is no way for it to pass this time around. The soil is primarily clay.
3) even IF it passed the perc-test, the size of the property vs the size of the building expansion, there wouldn't be sufficient room to lay out a traditional leech bed.
Though more expensive, from what I have read online, the Intermittent Sand Filter system is very compact. There are two concrete tanks, the sand filter bed which can be below grade and a couple of tranches for a "drainfield".
No, the effluent from the ISF system will just go into a drainfield, no irrigation.
I am just trying to get an idea of what the space requirements will be.
But if the minimum space requirements will take up too much space, then we don't want to waste money hiring an engineer to design a new system if it's not going to work out.
Ken L.
2) The soil will not pass a perc-test. I can't explain how it 'passed' the first time, but I know for a fact there is no way for it to pass this time around. The soil is primarily clay.
3) even IF it passed the perc-test, the size of the property vs the size of the building expansion, there wouldn't be sufficient room to lay out a traditional leech bed.
Though more expensive, from what I have read online, the Intermittent Sand Filter system is very compact. There are two concrete tanks, the sand filter bed which can be below grade and a couple of tranches for a "drainfield".
No, the effluent from the ISF system will just go into a drainfield, no irrigation.
I am just trying to get an idea of what the space requirements will be.
But if the minimum space requirements will take up too much space, then we don't want to waste money hiring an engineer to design a new system if it's not going to work out.
Ken L.
#4
07-17-12, 04:26 AM
I don't know about where you live but locally, the health inspector tells you where and what type of septic system you are to use. I think you have to pay for the permit before he actually comes out but I'm sure they'd tell you what the specs need to be over the phone.
#5
07-17-12, 06:19 AM
Super Moderator
The soil will not pass a perc-test.
You can only expand the home so much and must leave a certain amount of property for a septic system. You cant over build.
As marksr states, call the health department. They will tell you what you need and tell them the plans you have for the home. You may be in for a rude awakening.
How much space will you have?
Your very best bet IMO is to install the required gravel system and install two leach fields with a bull run valve. You switch between fields yearly and it will be the last septic you install.
Seepage pits take up less room then a traditional field, and the chamber systems also. ( I do not like the chambers though)
#6
07-17-12, 07:07 AM
Couple of years ago, I saw a drain field go into a tiny yard, maybe 20x50. It was black fiberglass and it had several levels of pipes, so it measured maybe 15x20x2 feet thick. What was I looking at?
#7
07-17-12, 08:11 AM
Group Moderator
I think the reason you don't find much information about ISF systems is that all I've seen are engineered and must be installed by a licensed installer. Basically no part of the process is DIY except writing a check to pay for it. In my area the Environmental Services Dept (Health Dept) will no allow or approve an engineered system to be installed by the homeowner. You can get some general idea online but I think you will end up having to contact an engineer or licensed installer to truly learn if it's feasible on your lot.
