Inground pool and abandoned septic tank?

[j_andrew_h]

We really could use help as we can't find these answers anywhere. We are currently on a septic system with a tank and leach field in our backyard. Our city just installed a sewage line on our street so we now have the option of connecting to the sewage line and abandoning our septic which we really want to do so we can finally have the pool in our backyard that we have dreamed of. Our yard is not super large so it would not be possible to place the pool a significant distance from the septic tank.

So here are the questions:

1. What distance should a pool be from an abandoned (destroyed and filled with concrete) septic tank can we put the swimming pool?
2. Should we try to have the septic tank removed completely rather than destroyed and filled which is the common option?

 

[Orion7319]

You will have to check with your local building authority or health authority about that one. We discovered after we bought our house that one of the previous owners moved the leach field at some point in time. A septic company and a permit for a new tank we found online shows an abandoned leach field right next to our pool. We wanted to have a pool built at one of our old houses and we found out the code here (at that time anyway) is for the pool to be at least 15 ft away from an active leach field. It will be different in each county in each state, so you really will have to find the right local officials to tell you.

 

[AQUA~HOLICS]

While excavating a pool uncovered an abandoned bomb shelter that was going to be within a few feet of the finished pool shell, contacted the steel engineering company and they revised the steel plans to take into consideration the open vessel next to the pool shell. Not a septic tank but both are empty vessels that have an effect on the pool shells outward forces.

 

[Bill1974]

Separate of what is permitted by code, you would need to fill and compact the soil in the abandoned tank and field to ensure settling is not going to be an issue. Depending on the conditions that might mean a lot of excavating and bringing in a lot of fill.

There might also be special handling for what is excavated and disposed off site.

 

[bigorangesky]

I had to deal with a septic tank as well, and it was much easier than I thought. I'd just let your PB deal with it while digging. If its in the way, I assume they will remove it, otherwise just leave it be. Plus city sewer is one less thing to worry about.

In our case, we have the main septic in the front yard and a smaller one in the back. It was only connected to a single half bath, that I think was added on, and not enough height/distance to run drains to the main drain. Whatever the reason, adding a whole septic tank must have been cheaper/easier than other solutions at the time. I needed to install a sewage ejector pump, then I could connect this bathroom to the main septic. Once I did that, had the old tank pumped out (septic company) and PB filled it in, but we left the concrete lid so did not have any settling issues. The tank was located under the pool deck (concrete with travertine pavers), no concerns about building on top of it. I could definitely smell the drain field when it rained, even though they only ended up digging through a small section.

 

[bmoreswim]

An abandoned septic tank filled with concrete is no different that a large underground boulder. The pool could be place quite close to it. Only the physical limitation of the solid block would be an issue.

The drain field is another issue, but that wasn’t your question.

 

[j_andrew_h]

Separate of what is permitted by code, you would need to fill and compact the soil in the abandoned tank and field to ensure settling is not going to be an issue. Depending on the conditions that might mean a lot of excavating and bringing in a lot of fill.

There might also be special handling for what is excavated and disposed off site.

Great additional considerations. Thanks.

 

[j_andrew_h]

I had to deal with a septic tank as well, and it was much easier than I thought. I'd just let your PB deal with it while digging. If its in the way, I assume they will remove it, otherwise just leave it be. Plus city sewer is one less thing to worry about.

In our case, we have the main septic in the front yard and a smaller one in the back. It was only connected to a single half bath, that I think was added on, and not enough height/distance to run drains to the main drain. Whatever the reason, adding a whole septic tank must have been cheaper/easier than other solutions at the time. I needed to install a sewage ejector pump, then I could connect this bathroom to the main septic. Once I did that, had the old tank pumped out (septic company) and PB filled it in, but we left the concrete lid so did not have any settling issues. The tank was located under the pool deck (concrete with travertine pavers), no concerns about building on top of it. I could definitely smell the drain field when it rained, even though they only ended up digging through a small section.

Thanks for sharing your experience; it sounds similar enough to mine. Thanks!

 

[j_andrew_h]

An abandoned septic tank filled with concrete is no different that a large underground boulder. The pool could be place quite close to it. Only the physical limitation of the solid block would be an issue.

The drain field is another issue, but that wasn’t your question.

Great, thanks!

 

[j_andrew_h]

An abandoned septic tank filled with concrete is no different that a large underground boulder. The pool could be place quite close to it. Only the physical limitation of the solid block would be an issue.

The drain field is another issue, but that wasn’t your question.

I would certainly appreciate your thoughts on the drain field as well and thank you again!

 

[bmoreswim]

I would certainly appreciate your thoughts on the drain field as well and thank you again!

The drain field is disturbed soil, soil with a drainage system below it, and soil with an artificially high amount of liquid, etc. having passed through it. I'd suspect a fairly complete removal and replacement of the soil/drainage components/soil below that, to get back to a usable state. But of course, any replacement soil would have to be compacted and professionally tested for the proper levels of compaction if the actual footprint of the drainage line removal was used to support anything. More generically, could you "use" the space by putting spoils from the pool dig over to of it and landscaping or planting grass? Sure.

And to clarify, my comments earlier on the septic tank are assuming that the tank has been fully pumped of sludge and is empty when filled with concrete. Thereby forming a solid concrete block.