How a Diverter Box Should Work

Diverter Box Tour, Common Issues and Maintenance
Location - Geauga County, OH

Tom Frank: This is a septic system with leach trenches and what’s called a diverter box. The leech trenches are divided into two halves. We have an upper half which is closest to the septic tank, and the lower half which is farthest away. There are two boxes here...this box is the diverter box, this is the first trench on what will be the upper side. Currently this system is using the upper side. To switch a diverter box you would take it...this pipe goes down to the lower side...we’re not using it, it’s shut off, and that's the reason for this elbow. Take that off and put it on here. Now, we’ll be using the lower side and giving the upper side a rest. If you don’t know which pipes are which, easiest usually is to try and line up with the septic system, the septic tank which would be this line here coming in. You do not want to put the elbow on there because that will cause problems up there in the septic tank. You want to switch these two on the trenches; the one going to this box, and the one that comes out, and it runs along and goes down into those lower boxes. The reason for that is that this water is still a little bit dirty when it comes out of the septic tank. By giving this side a rest, the stuff that the water carries with it is dissolved in the same way as the water, the little particles will go out and flow into the trench...by giving this one a rest for a year, we try and let it remediate itself and let nature take its course and drain some of that material so when you put the water back to it again, the water can get back into the soil. Not all systems are going to last a full year; some of them you have to do a little bit sooner. If you start to get a wet spot out over the side that you’re using, you may have to change it before the year time. If you can let it go up to a year that is the best thing to do. The reason for the year is to get a full cycle of seasons...we don’t want to be changing it in October and April, and that side that we’re not using and resting through the winter months doesn’t get a good warm soil for the bacteria to start to remediate itself and let it try and digest it and take that material away.

TF: The solids reach about 25-30% of the volume...and that’s the amount of upper crust and the amount of lower crust, it’s about 25-30%. So that total volume. So, the reason for that is you want those things to settle out and raise to the top. When it starts to get above that 30%, then it starts to send out through your water to the secondary treatment...and that’s something you don’t want. Everybody wants to know when their tank is full; well, you don’t want your tank to be full, that’s kind of like an oil filter when it is full, it’s too late. You want to pump it when it’s ready to be pumped. That bacteria has to work to get out of the pipe and into where the actual issues are. So by us trying to get the heavy stuff out of the pipe and get the pipe cleaned out, we put the material in there and it can go out of the pipe and into the stone where it can work a little bit quicker and a little more effectively, so we’re cutting down on the work that it has to do a little bit.

Matt: And why are we concerned about what happens when the water gets out of the perforated pipe and into the stone?

TF: Because what will happen is that it will get so much of that heavy sludge in there; that instead of going out of the pipe and instead of going into the soil, it will start to surface and it will start creating wet spots. Or, it will just overflow the box. Like, you’ll just have a box that will just be running out across the top.

Matt: Because of the pipe perforation...

TF: Because there’s no place for the stones, the soil around it and all that and it won’t accept the water anymore. We want it out of those trenches and go down into the soil. And so, after a period of time...now, not everyone we can fix, either. I mean there’s some of them that do what we call bleed, they surface right from the very beginning because they were put in in maybe a bad soil or something. So what we want to try and do is we want to try and...um, you know if it’s working for 25 years and they’ve never had a problem with it and it’s not bleeding but now all of a sudden in the last year it has started to bleed a little bit; it’s started to surface, then those are the ones that we we can try and remediate and fix...but we need to have some history on the system

Matt: Sure, to know what you're dealing with.

TF: Yes, to know what we’re dealing with, and sometimes we’ll go as far as having a soil scientist come out and look at the soils around the system to tell us if we can get the water into the soil and if the soil will take the water away, or is it just such a bad soil that it won’t...in our area here, we have a small percentage of soil that was actually suitable for leech trenches, because we have seasonably high water tables. A water table that comes up within the top of the ground is 6-8” from the top of the ground from October through April. So there's a soil process...there are air pockets in the soil, and those air pockets will be full of water all winter long. So you’re taking and you have a wet sponge out here and you’re trying to put more water in a wet sponge, it won’t work.