The basin requires a 2- to 4-inch tee-wye connection, cut
into the existing sewer or septic line, with a check valve on
the ejection side to prevent refilling of the basin (Figure
2. The sump basin receives wastewater from bathroom
fixtures. The grinder pump liquifies the sewage and pumps it up
to the main drain line exiting the house. A check valve
prevents gravity backflow into the basin.
For the piping above the basin, Schedule-40 PVC provides a
quick and simple tie-in.
In my experience, sometimes the pump will create excessive
vibration in the piping. In these cases, installing a Fernco or
Mission flexible connector in the line will absorb the
vibration and prevent stress from building up at the rigid
connections. This fitting also serves as an easy disconnect
should the basin require servicing.
As with any plumbing drain, venting is important. Without a
vent in the sump basin, the pump action would create a powerful
vacuum. The basin includes a vent connector, either molded into
the lid or the body of the basin, which eliminates the need to
disconnect the vent pipe when removing the lid.
The inlet pipe from the bathroom fixtures connects to the
basin inlet connector, completing the drainage installation.
Once this connection is made, I backfill the excavated areas
with sand or gravel and repair the concrete surface. I take
extra care with the patching process, making sure that the
floor is restored to a flush, smooth condition. Any lumpiness
in the floor finish will telegraph through carpet or vinyl
bathroom walls are framed, my plumber completes the rest of the
rough plumbing above the floor just like any installation.
Tying the fixture vents back into the main stack finishes the
The ejector pump can be either hard-wired or have an
integral plug, so I have my electrician wire a connection near
the tank location, and the system is operational (Figure
3. Only the top of the basin shows, allowing
service access. Plug-in power simplifies the
An option you may want to add is an alarm system, which
monitors the basin level. An integral float furnished with the
pump provides automatic on-and-off action, in response to
usage. In case the pump does not cycle, an audible alarm sounds
to warn against usage until the system is checked. Few
manufacturers supply these alarms as part of their package, but
I feel it’s a worthwhile investment for both the customer
and the contractor. Both battery and electric alarm models are
available. Line-voltage alarms should not be plugged into the
same circuit as the pump, because if the pump has failed due to
an electrical fault in that circuit, the alarm should still
function. Alarm costs vary, but average about $50. I highly
recommend their use, especially if children are going to use
the new bathroom.
Ejector pump prices currently start at about $625 for
self-contained systems and $325 for an in-floor setup. They are
available from plumbing supply houses and some larger home
Jim Eggert owns and operates Eggert Construction,
providing design/build services in Branford, Conn.
Makers of Ejector
Zoeller Pump Co.
Water Ace Pump Co.