Converting Gravity Sewer to Overhead

[lj973gm]

This is long winded, but there is not really any other way to state the situation at hand.

I am in northern Il and have an odd scenario regarding the sewer setup at my home.

Home (1950's) was originally on septic. At a some point and time the original homeowner sold a portion off the land off where the septic tank was located and converted to a gravity sewer which is about 200' long out the back of the property. The oddity is that the sewer is tied into a private sewer system of a condo/apartment complex, which is part of a different town. The back of our property line, is the dividing line of two towns.

The complex has a 10" sewer main and came to find out we are the lowest point of the roughly 2000-2500' system. Original homeowner tied the floor drain to a sump pit with a piece of 1-1/4" which clogged with a disposable wipe and other debris, so we flooded. Lots of floaters that were not from my family

So a backup happened and then a backwater valve/check valve was installed. We are now at the mercy of the complex to clear to blockage when they occur. It typically happens on off hours and holidays and getting someone out to water jet it is not the easiest. There have been three backups this year. The complex does not maintain the sewer to clear the grease logs and disposable wipes that litter the system.

My home is a single story, which has a half bath and a full bath on the first floor, which route straight down into the basement gravity sewer. The First floor kitchen exits out the basement wall into a grease separator and ties into the gravity sewer at some point exterior of the home. The basement consists of a full bath, washing machine and floor drains.

I have a couple of options.

Option #1
Tie into the correct sewer for my town with an overhead sewer. This would also allow me to obtain city water and keep the well for irrigation. The town will not let me obtain water unless we have an approved sewer which they state is required to be tied to the correct town. The cost on this is very high. It involves rerouting the sewer from the rear of the home to the front and directional bore under a county road. Estimate 5 years ago was around $20K

Option #2
Intercept existing gravity sewer with an ejector pit. Relocate the first floor full bath to overhead, so a bathroom can be use during pump failure. Half bath and basement plumbing would route to the ejector pit. Cost is going to considerably lower than the first option.

I am planning to go with option #2. Since I am looking to resolve the problem quickly and not deal with multiple permits for the county and city, cost factor and the current time of year.

I would like to convert to overhead sewer and keep all work within the home. Is there any reason why scenario listed below consisting of intercepting the current sewer with an ejector pit, 2" from the pit would route vertically to the the floor joists of the basement ceiling, then horizontal for a short distance, and then have a 4" vertical that ties into the existing gravity sewer before it leaves the home?

Attached is a picture of basically what I am looking to achieve.

I do not plan to tackle this task myself, but will perform the excavation of the floor and earth for the plumber prior to arrival. I am a tradesman who typically performs all work myself, but I do not want to put my family into the scenario since this is not my trade and I would like it to meet or exceed code for future sale of the home at some point.

I spoke with a commercial plumber on my jobsite briefly about the matter and he has not scene this situation. He stated typically the gravity is converted to overhead as shown in this image. The downside is coring a hole in basement wall, excavating the backyard and increased costs.

 

[Reach4]

1. There may be a program to help pay for overhead sewers. Maybe not.
2. Check the system at http://www.floodexperts.com/services/flood-control-systems/
That buries a big pit in the yard, and does not involve redoing the plumbing in the house.

I could imagine that the people operating the sewer may not buy into it, but I think it would be on the order of $7000 or $8000 so.

Your conversion to overhead sewer, which your drawing does not show, is best. The "after" part of your second drawing shows what is normally considered to be an overhead sewer. This is not to say that what your first drawing shows is into good. Budget maybe $15000 to $20000 for the overhead sewer. Try to get somebody who will keep the topsoil separate and will compact the filled ground back with sledgehammers or a serious power tool. Don't let them mound clay up. Nothing will grow there, and you will need to get that removed and replaced with topsoil if you want decent grass later.

 

[Sponsor]

 

[CountryBumkin]

Can you install a new septic tank and drain field somewhere (if you have the room)? That would surely be cheaper than tying into the city sewer.

 

[lj973gm]

CountryBumkin, a septic is no longer an option due to lot size and the city does not allow them any longer. Lot falls just under an acre after the

portion was sold off and I believe a number of years back they stopped allowing new septic and wells.

Reach4, I would rather have the work performed within the home since the basement is only partially finished. I was mainly trying to think of a reason why the first image showing the pit intercepting the existing gravity sewer would not be ideal. The only thought I can come up with is that the vertical 2" line and the 4" horizontal and vertical line going back into the existing sewer might not have enough capacity.

What I mean is that during a backup the 4" vertical pipe would be filled about 2' above the basement floor with sewage before sewage would see day light out of a manhole cover at the condo association. So a typical 24" pit depending on depth holds 40-70 gallons which could be a greater amount of available empty pipe for the sewage to go into before the sewage/water seeks it own level at various points in the sewer system.

Could you please clarify what you meant in this statement?

"Your conversion to overhead sewer, which your drawing does not show, is best"

What were you referring to??

Thanks for the knowledge.

 

[Reach4]

Reach4, I would rather have the work performed within the home since the basement is only partially finished. I was mainly trying to think of a reason why the first image showing the pit intercepting the existing gravity sewer would not be ideal. The only thought I can come up with is that the vertical 2" line and the 4" horizontal and vertical line going back into the existing sewer might not have enough capacity.

What I mean is that during a backup the 4" vertical pipe would be filled about 2' above the basement floor with sewage before sewage would see day light out of a manhole cover at the condo association. So a typical 24" pit depending on depth holds 40-70 gallons which could be a greater amount of available empty pipe for the sewage to go into before the sewage/water seeks it own level at various points in the sewer system.

Could you please clarify what you meant in this statement?

"Your conversion to overhead sewer, which your drawing does not show, is best"

That was not based on logic, but on rules and definitions that a friend ran into when facing choices much like you are making. The rule was that the new connection to the sewer was via a new hole in the side of the basement wall. We tried to figure out why they made that rule, and we suspected that insured there was no hidden connection under slab remaining. They defined what they called an overhead sewer, and you had to meet their definition to get the subsidy money.

If you are not getting subsidy money, then you can do what makes logical sense, and you can call it what you like. Since you are not already on their system, your town may not want to part with any of their subsidy money. It is worth checking however.

 

[CountryBumkin]

With Option #2, I don't see how this is going to fix your problem. If the main sewer line you are connect to is over capacity, the only benefit to going overhead is the additional capacity of the added pipe. That probably won't last long before it is full (when main sewer is clogged or over capacity). Plus you don't know the main sewer is clogged until the backup reaches your home. Then its too late to switch bathrooms or do anything.

You still need to add a backflow preventer to keep from flooding your basement.

IMO, you need to add a large enough holding tank for those times when the main sewer is clogged or over capacity (how large - ?) or bite the bullet and run a new connection to tour township sewer line.

 

[Reach4]

With Option #2, I don't see how this is going to fix your problem.

It causes the exiting sewage to have an above-ground "head". So even if the backpressure in the sewer in the yard rises it cannot force water up into lj973gm's basement.

If the power goes out, the main floor plumbing can still flush out through the sewer into the yard, and perhaps into somebody else's basement. :-(

 

[DougB]

Option #1
Tie into the correct sewer for my town with an overhead sewer. This would also allow me to obtain city water and keep the well for irrigation. View attachment 37135

Why not do the right thing?

 

[lj973gm]

Why not do the right thing?

The tune of 20K-30K

Whether I tie into my own town or rework the existing sewer an ejector pit and overhead will be needed to ensure backup does not happen again besides the flood control system listed above that would likely cost in the same ballpark.

I am looking to know the downside of option #1 shown in the first post. Is it the capacity of the line to take the discharge from the pit that they typically configure the hope with option #2?

 

[Jadnashua]

A typical pit for an ejector pump is not very big. In reality, if the power was out, you would quickly fill it up and then things would start to backup into your home.

If you can't put in a new septic system, your only viable choice is to go to your town's sewer. Having the home on town sewer and water is a big selling point, should you get to that.

Depending on the depth of the sewer line, running it around your home to the front may not be a major deal. You will potentially need a cleanout or maybe two, depending on the amount of change of direction, but it might be easier than relocating the line and going out the front wall of the home. Your drain line needs slope all the way. Depending on the size of the pipe, you might be able to get by with less than the 1/4"/foot (1/8"/foot might be allowed on 4" and larger pipe). Your town may not want you to tear up the road, but it might be a cheaper way verses directional drilling (but probably not), if they'll allow that. A poorly done patch, though, can be an issue. What is the soil like where you live, and do you have to deal with any ledge or big rocks? how much elevation change is it to where your town's sewer line is verses where it would come out of your house? That will somewhat determine if it is feasible.

 

[Reach4]

I am looking to know the downside of option #1 shown in the first post.

Nearly none if you are paying for it, as I understand it. If there was a remaining connection that you did not know about, that would not be good. Unlikely. That exit piping is under a bit of pressure potentially. As long as the pipe holds, fine.

While digging in your basement floor, I would put in a sump with pump for ground water. Dump that water into the yard on the low side. Some use a pop-up for that. You can put in perf pipe in a trench to pick up water over a bigger space, or you can just drill some holes at the same level as the gravel just below the concrete. In that case you are hoping that the gravel can let water travel. Usually it works.

 

[lj973gm]

I plan to run a camera to confirm the setup would prove to resolve the problem at hand, no reason to throw money at the problem and only cure 90% of the issue and have a backup still. Thanks for throwing this out there since it could easily get overlooked.

There was a drain tile system installed internally of the home 2 years ago. Perimeter is 3" SDR dumping to a 24 x 36 basin, ion genesis, 2 pumps on the alternator and a third for backup. Two battery system. Once they see daylight they dump into a 3" that runs out about 40 feet and then the last 15' is perforated surrounded by stone about 4' under that turns up to a pop up.

There was a concern during the last couple of 50-100 year storms we had a few years back. The home only had a concrete basin originally with a hole in the bottom which was inadequate. The township reworked the sewer in the area a few blocks down the road about a year after the drain tile was completed and since this then the pump cycle about 60% less.

 

[lj973gm]

A typical pit for an ejector pump is not very big. In reality, if the power was out, you would quickly fill it up and then things would start to backup into your home.

If you can't put in a new septic system, your only viable choice is to go to your town's sewer. Having the home on town sewer and water is a big selling point, should you get to that.

Depending on the depth of the sewer line, running it around your home to the front may not be a major deal. You will potentially need a cleanout or maybe two, depending on the amount of change of direction, but it might be easier than relocating the line and going out the front wall of the home. Your drain line needs slope all the way. Depending on the size of the pipe, you might be able to get by with less than the 1/4"/foot (1/8"/foot might be allowed on 4" and larger pipe). Your town may not want you to tear up the road, but it might be a cheaper way verses directional drilling (but probably not), if they'll allow that. A poorly done patch, though, can be an issue. What is the soil like where you live, and do you have to deal with any ledge or big rocks? how much elevation change is it to where your town's sewer line is verses where it would come out of your house? That will somewhat determine if it is feasible.

If the home has a power loss, water is also cut since I am on a well once the pressure in that tank is out. I have a roll up generator for once I would get home. The main full bathroom on the first floor would be routed overhead to ensure there was a usable bathroom would be available in the event of pump failure or power loss. The kitchen is already on overhead to the best of my knowledge, so the remaining items that would be on the ejector would be the basement and a half bath on the first floor.

Going with my actual towns sewer the situation would be the same as going to the private condos sewer. The main difference is that a backup from the city is less likely than the condo backing up.

Since I pit is needed either way for the basement the best option is to likely drop a pit and reroute the main bathroom and tie into the existing sewer to the condo and in the near future start investigating the process to tie into the city sewer. I started to check the permit process when I moved in 6 years back and was told the local town is not bad, but dealing with Cook County for directional boring under the road will be a slow process to gain approval.

Flat land with soil and clay, nothing rocky with large elevation changes. I do not know the depth or any info regarding the city sewer besides it is about 200' away and across a county road.