sewage backflow thru sump

[kdahlin]

Greetings all, my first post.

My washing machine sump is leaking sewage smell into basement.

I have a washer downstairs in the basement that is hooked up to a standpipe. THe stand pipe empties into an open-faced hole in the poured concrete floor that looks like a milk crate inside. From there a pole sump submegered is supposed to pump it up 8 ft to an overhead main sewage line.

(The main pipe falls backward towards the sump which is the end of the line. Seems to flow the wrong way. Two toilets are attached further up from upstairs.)

Is there a closed faced/sealed system for doing the sumps job that will be safer for family health? Been reading here and I know I have to keep the stand pipe. But the open sump is a health hazard leaking sewage.

I want to keep the washing machine where it is. Yet, I am afraid anything new we put in will just leak sewage as well becuase the grade of the pipe falls to this connection.

Any suggestions?

[Java_Bob]

do you have a check valve inline with the discharge??

[kdahlin]

there was no valve on the pipe, just a joint.

[LazyPup]

From your description you have a number of serious problems here.

1. Open sump pits are intended to receive any storm runoff water that may enter the structure. Under no circumstances may any household effluent be discharged into a sump pit.
2. Sump pumps are to be discharged outdoors onto the landscape or into an approved storm drain. Under no circumstances may a sump pump be directly connected to a house DWV (Drain, Waste &Vent) sanitary drain line.
3. Washing machines are required to discharge into an approved “indirect waste receptor” which is either a laundry standpipe or a laundry tub sink that is connected to the house DWV system.
4. Whenever it is necessary to create a drain at a point that is physically lower than the gravity flow house sewer & main drain, the drain must discharge into an approved “Sewage Ejection Pump” which then lifts the effluent up to the gravity flow drain system.

I am attaching an illustration that shows numerous types of sewage ejection pump systems commonly used in residential applications.

Generally Rules for a Sewage Ejection Pump:
1. Generally sewage ejection pump is installed in a watertight crock that is installed below the basement floor level. The fixtures below the gravity flow drain are required to have traps & vents per standard code practice and they discharge into the Sewage Ejection Pump vessel by means of gravity flow.
2. Per code, all sewage ejection pump systems, regardless of size, must have a completely watertight receiver vessel that is fitted with a watertight removable cover.
3. The sewage ejection pump vessel MUST BE equipped with a dedicated 1-1/2” vent through the roof of the structure. This vent may not be combined with any other vents in the structure.
4. The pump discharge line MUST BE a 2” line except, if the pump is equipped with a “Macerator” the discharge line may be reduced to 1-1/2”. (A macerator is a cutter blade attached to the pump impellor that reduces solid waste (fecal matter) into slurry in basically the same manner as a garbage disposal before pumping).
5. The vertical riser from the pump must be equipped with a manually operated DWV rated gate valve and a DWV rated backflow preventer.
6. At the top of the riser you must install a Wye & 1/8 bend with the riser connecting to the side inlet and the discharge end of the Wye connected to the horizontal line. The inlet end of the Wye must be fitted with a cleanout cap.
7. On the downstream end of the sewage ejection pump line where it attaches to the house gravity flow line the sewage ejection line must rise to an elevation above the gravity flow line and the ejection pump line must be connected to the gravity line by means of a Wye & 1/8bend with the Wye inlet rising vertical from the top of the gravity line (see illustration).
8. Under the IRC the minimum output of the pump must be 14.2gpm (Under the UPC-Uniform Plumbing Code- the minimum output of the pump must be 20gpm).
9. Under the IRC the gravity flow drains receiving discharge from a sewage ejection pump must be sized at 1.5DFU (Drainage Fixture Units) for each Gallon/minute of pump discharge, (Under the UPC the line must be sized to receive 2DFU’s per GPM).

Pay very close attention to the load calculation information in points 8 & 9. Many homeowners and DIY’ers see a 2” discharge line on a sewage ejector and they erroneously assume that the line may be connected to the nearest gravity drain line which is 2” or greater.

Per code, all DWV lines are sized by the DFU load on that line therefore when selecting a place to connect the sewage ejector we must compute the DFU load of the sewage ejector and add that value to the existing load on the line we are attempting to connect to.

Under the IRC, when computing the DFU load value of the sewage ejector we are required to allow 1.5DFU for each GPM of pump rating or 1.5DFU x the code minimum pump rating of 14.2gpm, whichever is greater, thus the minimum DFU load for a sewage ejector is 1.5dfu x 14.2gpm = 21.3DFU’s.

Under the IRC a 2” branch line is rated for a maximum 6DFU’s and a 3” branch line is rated for a maximum of 20DFU’s, therefore the sewage ejector itself has a greater load than what is permitted on the pipe, not to mention the pre-existing load on the pipe.

Now let us consider the existing load on your house “Main Drain”. In the post you stated that there are two toilets connected to the drain line. From that we can conclude that you either have a bathroom and a half bath or two complete bathrooms.

Under the IRC from table IRC-3004.1 & IRC-3201.7 the fixtures are rated at the following DFU loads;
Lavatory 1DFU
Tub/shower 2DFU’s
Shower Stall 2DFU’s
Watercloset (1.6gpf or less) 3DFU’s
Watercloset (greater than 1.6gpf) 4DFU’s
Kitchen sink 2DFU’s
Laundry standpipe 2DFU’s
Laundry sink 2DFU’s

For the purpose of illustration I will assume you have two full baths with the standard bath group, 1 lavatory (1DFU), tub/shower (2DFU) and a 1.6gpf watercloset (3DFU) for a combined load of 6DFU’s. You have two bathrooms and obviously you have a kitchen sink (2DFU) for a total combined load of 14DFU’s. (with the washing machine standpipe (2DFU) the load would be 16DFU’s)

Note that we did not include the washing machine in our calculations because that portion of the load will be included in the Ejection Pump load.

We have now concluded that the existing load will be 16DFU and the ejection pump will add another 21.3DFU’s for a total combined load of 37.3DFU’s.

The IRC allows a maximum of 42DFU’s on a 3” house main drain and house sewer providing they are run with a ¼” per foot pitch, however there is an exception in the code that will allow a 3” main drain to be run with a 1/8” per foot pitch with the expressed approval of the AHJ however the reduced pitch also reduces the allowable load to 36DFU’s. In this case we could not install a sewage ejection pump unless we either increase the pitch to ¼” per foot, which is generally impossible to do or we would have to replace the entire house main drain and house sewer with a 4” line.

[kdahlin]

wow

That is a lot to take in! Thanks for the input. Very thorough.

Previously the sump was connected to the house main drain sideways rather than vertically as you show in your diagram. I think that would help quite a bit.

In the diagram I can hook the standpipe directly into the sealed tub right?

I do not intend to put a toilet in downstairs and this is only for the washing machine. Do you still recommend the sewage ejector pump vs any old pump?

Does the vent have to go through the roof (from basement)?

Does the size of the basin go by a caculation of how much water the washing machine holds?