Adding a drain line to existing drain line

[Farmskis]

Hello,
I would like to install a whole house filter that requires a drain line. It will backwash with about 7-10 gpm. I have included pictures to show you what the area looks like. I would like suggestions on how to install a drain and if I am able to use this line in my basement. I ideally would want to run a line outside and drain it out in a wooded area or dry well in our back yard but I don’t have the time to lay the line and want to get the water filtered sooner so I will use the septic for a year or two until I can either get a dry well or use the wooded area.

see Pictures for details. In general though
- 2” pvc in basement located 12” from ceiling.
- drain line drains laundry, and upstairs sinks or kitchen sink Before flowing into a larger 4” line
- I believe the builders left a connection spot to use for this very purpose

what parts/sizes would you use to build this drain add on? air gap?

filter will have a 3/4 drain line out I believe possibly 1/2“.
thank you for the suggestions.

 

[MicEd69]

The item you think is a possible connection is a cleanout and cannot be used as a tie-in point. And the backwash piping cannot be directly connected to the sewer line but needs an air gap just like your washer drains into a standpipe. With your water heater right there, there should also be a floor drain nearby. For a temporary setup, you could lay the backwash discharge hose/piping on the floor and drain it into that floor drain. That would leave the backwash line empty which would be a good thing.

The second easiest possibility would be to route the backwash line up to the washing machine standpipe and use it for the backwash. That would involve drilling a hole in the floor, but no actual sewer piping work would be required. This option would leave the backwash line full of water, which may not be desired.

The other way to do this would require additional sewer connection at the 4" stack. You would need to add like a 2" connection to the stack and follow the same code requirements as a washing machine connection. See the sketch below. The line to the right in the sketch would be attached to the 4" stack. And depending on the elevation and configuration of the backwash system, and the distance to your 4" stack, this may also leave the backwash piping full of water.



Here is another sketch with some dimensional restrictions for the standpipe. Disregard the reference to the waste stack as you will need the AAV for a vent as in the above sketch. And the 30" max (some areas) can be 42" if you are in an Internation Plumbing Code (IPC) area.



Bottom line, I would go for the floor drain option. If the floor drain has an issue with the flow, you can add a 5-gallon bucket with a smaller drain line to provide a surge volume to allow the drain to accept the flow without puddling around the floor drain.

 

[Farmskis]

Thank you for your help!

The item you think is a possible connection is a cleanout and cannot be used as a tie-in point. And the backwash piping cannot be directly connected to the sewer line but needs an air gap just like your washer drains into a standpipe. With your water heater right there, there should also be a floor drain nearby. For a temporary setup, you could lay the backwash discharge hose/piping on the floor and drain it into that floor drain. That would leave the backwash line empty which would be a good thing.

The second easiest possibility would be to route the backwash line up to the washing machine standpipe and use it for the backwash. That would involve drilling a hole in the floor, but no actual sewer piping work would be required. This option would leave the backwash line full of water, which may not be desired.

The other way to do this would require additional sewer connection at the 4" stack. You would need to add like a 2" connection to the stack and follow the same code requirements as a washing machine connection. See the sketch below. The line to the right in the sketch would be attached to the 4" stack. And depending on the elevation and configuration of the backwash system, and the distance to your 4" stack, this may also leave the backwash piping full of water.

View attachment 37088

Here is another sketch with some dimensional restrictions for the standpipe. Disregard the reference to the waste stack as you will need the AAV for a vent as in the above sketch. And the 30" max (some areas) can be 42" if you are in an Internation Plumbing Code (IPC) area.

View attachment 37089

Bottom line, I would go for the floor drain option. If the floor drain has an issue with the flow, you can add a 5-gallon bucket with a smaller drain line to provide a surge volume to allow the drain to accept the flow without puddling around the floor drain.

Thank you for your help! Unfortunately there is no floor drain.

1. Running up to the laundry room is definitely an option I will look closer at because it is right near that area. I am just going to check what would all be involved as for drilling the holes to get the pipe up to it to dump into that same stack as the washing machine does.

2. In looking at your connection setup to the 4 inch pipe, would the top of the pipe need to be higher than the washing tub basin or could this all be done below in the basement between the top of the pipe and the ceiling? (I’m guessing the diagram might just be an example for a washing tub.) It would definitely be above the filter but since the washing tub is located one floor up it would be below that.

 

[Farmskis]

Thank you for your help!

Thank you for your help! Unfortunately there is no floor drain.

1. Running up to the laundry room is definitely an option I will look closer at because it is right near that area. I am just going to check what would all be involved as for drilling the holes to get the pipe up to it to dump into that same stack as the washing machine does.

2. In looking at your connection setup to the 4 inch pipe, would the top of the pipe need to be higher than the washing tub basin or could this all be done below in the basement between the top of the pipe and the ceiling? (I’m guessing the diagram might just be an example for a washing tub.) It would definitely be above the filter but since the washing tub is located one floor up it would be below that.

Here is a photo of the 4” pipe I could tie into. Would I be able to use that clean out and extend the 4 inch pipe to the left? Put the clean out on the end of the extension And add the drain between the original clean out and the new one I add?
Or would I have to completely remove the clean out, extend pipe to the left and re pipe the 2” pipe going in as well as add the new drain and then put another clean out at the end of the 4 Inch new section?

 

[MicEd69]

OK, I may have misinterpreted you description of your piping. When you said the 2" line was running into a 4" line, I thought you meant the 4" line was vertical, that being the waste stack. As there is no floor drain near the water heater, does that 4" ever drop to the basement floor level, or does it exit at a higher level and your basement water only handled by a sump and pump?

As I indicated, the backwash line cannot be hard piped into the sewer line. There must be an air gap and a P-trap to connect this to a sewer, just like your washing machine. The first sketch was specifically for a washing machine and was just to show the P-trap and AAV, so disregard the reference to the washing machine. Also disregard the reference to the washing machine in the second sketch. This standpipe will be solely for your filter backwash. As such, using a line at the basement ceiling level is impossible as there is no room to install the standpipe for the backwash.

So, if the 4" line ultimately drops to and through the basement floor someplace, you will need to install a standpipe like the first sketch shows using the dimensions for the P-trap and riser shown in the second sketch. This standpipe can be installed near the filter and as long as the AAV is within 8 feet of the riser, and the drain line is sloped 1/4" per foot all the way to the main 4" waste stack. But if your main sewer exits the basement through a wall well above the floor level, then you must have a sump and pump that handles any water that gets into your basement, into which you could drain the backwash water. That would be a great option, especially if it is somewhat close to the filter. If this is the case, you may just want that to be your permanent installation. Sure, your using electricity to pump some water out, but is sure beats digging and installing a drywell and underground pipe.

To use the existing standpipe on your washing machine, you could run into problems if the backwash is on a timer and the washing machine just happens to be discharging at the same time. But the 2" standpipe can handle the projected 7-10 gpm backwash. I would use a hose at least through the floor and into the standpipe. And you will need to figure out how to get both the washing machine discharge hose and the filter hose into the standpipe. If the standpipe is installed in a washing machine outlet box, that could be an issue. You do not want those two hoses connected to each other. If the standpipe is just a plain 2" PVC pipe, just cut 18"-24" off and install a 2"x3" reducer and increase the top portion of the standpipe to 3".

 

[Farmskis]

OK, I may have misinterpreted you description of your piping. When you said the 2" line was running into a 4" line, I thought you meant the 4" line was vertical, that being the waste stack. As there is no floor drain near the water heater, does that 4" ever drop to the basement floor level, or does it exit at a higher level and your basement water only handled by a sump and pump?

As I indicated, the backwash line cannot be hard piped into the sewer line. There must be an air gap and a P-trap to connect this to a sewer, just like your washing machine. The first sketch was specifically for a washing machine and was just to show the P-trap and AAV, so disregard the reference to the washing machine. Also disregard the reference to the washing machine in the second sketch. This standpipe will be solely for your filter backwash. As such, using a line at the basement ceiling level is impossible as there is no room to install the standpipe for the backwash.

So, if the 4" line ultimately drops to and through the basement floor someplace, you will need to install a standpipe like the first sketch shows using the dimensions for the P-trap and riser shown in the second sketch. This standpipe can be installed near the filter and as long as the AAV is within 8 feet of the riser, and the drain line is sloped 1/4" per foot all the way to the main 4" waste stack. But if your main sewer exits the basement through a wall well above the floor level, then you must have a sump and pump that handles any water that gets into your basement, into which you could drain the backwash water. That would be a great option, especially if it is somewhat close to the filter. If this is the case, you may just want that to be your permanent installation. Sure, your using electricity to pump some water out, but is sure beats digging and installing a drywell and underground pipe.

To use the existing standpipe on your washing machine, you could run into problems if the backwash is on a timer and the washing machine just happens to be discharging at the same time. But the 2" standpipe can handle the projected 7-10 gpm backwash. I would use a hose at least through the floor and into the standpipe. And you will need to figure out how to get both the washing machine discharge hose and the filter hose into the standpipe. If the standpipe is installed in a washing machine outlet box, that could be an issue. You do not want those two hoses connected to each other. If the standpipe is just a plain 2" PVC pipe, just cut 18"-24" off and install a 2"x3" reducer and increase the top portion of the standpipe to 3".

You are correct in that the pipe never reaches ground level. It exits out of the house about 5 ft above the floor.

So I guess that leaves either a sump installation, which we do not have. Or the routing to the laundry.

 

[Farmskis]

You are correct in that the pipe never reaches ground level. It exits out of the house about 5 ft above the floor.

So I guess that leaves either a sump installation, which we do not have. Or the routing to the laundry.

Is there an easy solution to add a sump and sump pit strictly for this filter?

 

[MicEd69]

So I guess that leaves either a sump installation, which we do not have.

Do you have a walkout basement? Just wondering what would happen if/when your water heater or the filter springs a leak. How would you drain your water heater?

 

[MicEd69]

Is there an easy solution to add a sump and sump pit strictly for this filter?

 

[Farmskis]

Do you have a walkout basement? Just wondering what would happen if/when your water heater or the filter springs a leak. How would you drain your water heater?

 

[Farmskis]

It is a walk out. But it is only a walk out through the basement door into the garage. Would really be no fun if had to drain it. Would have to probably drill a hole through a wall into the garage.

 

[Farmskis]

View attachment 37110

View attachment 37111

Does this sump need to be buried into the floor. I know it really is designed to be but does it need to be? Where do I hook this into the drain? Near where it exits the house into the septic?

 

[MicEd69]

No, this unit, and several ones like it, are not designed to be installed below floor level. I'm not recommending this particular one, just letting you know this is yet another option. These are used for items like sinks and washing machines when they cannot be drained into a gravity sewer, just like what you have.

You will need to install a check valve and a manual valve on the discharge line, and you need to enter the overhead line on the top of the line. Run your line up between the floor joists and come back down into the 2" using a combo wye and a pair of street 90s. The vent from the sump will also need to be installed so that it vents outside and should be covered with flue cap.



Following is very rough sketch, just don't have time to make it pretty. The vent does not have to go above the roof in this case, but I would put it up to under the eaves perhaps. It is needed so the sump can breathe; air will come out as the sump fills and will come in as the pump discharges the water to the sewer. You will likely need to throttle the discharge some to match the incoming water flow. You do not want the pump to cycle on and off repeatedly during operation.

 

[Farmskis]

No, this unit, and several ones like it, are not designed to be installed below floor level. I'm not recommending this particular one, just letting you know this is yet another option. These are used for items like sinks and washing machines when they cannot be drained into a gravity sewer, just like what you have.

You will need to install a check valve and a manual valve on the discharge line, and you need to enter the overhead line on the top of the line. Run your line up between the floor joists and come back down into the 2" using a combo wye and a pair of street 90s. The vent from the sump will also need to be installed so that it vents outside and should be covered with flue cap.

View attachment 37114View attachment 37115View attachment 37117

Following is very rough sketch, just don't have time to make it pretty. The vent does not have to go above the roof in this case, but I would put it up to under the eaves perhaps. It is needed so the sump can breathe; air will come out as the sump fills and will come in as the pump discharges the water tom the sewer. You will likely need to throttle the discharge some to match the incoming water flow. You do not want the pump to cycle on and off repeatedly during operation.

View attachment 37118

Thank you for your drawing and knowledge! This makes perfect sense and I understand your explanation with one question.
One term you mentioned was “throttle the pump” would I do this by closing manual valve to match the input with the output flow rates? Or is there a way to adjust the pump output on the pump itself?
Again thank you for your help!

 

[MicEd69]

You are correct, you throttle the valve in the discharge line. You do not need to be super precise; you just don't want the pump to cycle on and off every few seconds. I'm not sure how much total amount your backwash will provide, but most pumps will provide around 40 gpm. So, with a sump size of around 6 gallons, the pump will start pumping when there is maybe 2-3 gallons in the sump, if your input to the sump is 10 gpm, the pump will empty the sump in about 6 seconds and start again in like 12 to 18 seconds.

By throttling it to better match the input flow, you can make the pump run for longer than 6 seconds, which lengthens the life of the pump.