Sewage Ejector Pumps

An ejector basin is a sealed pit, not an open sump. Sanitary waste is going into it, so the cover is gasketed and bolted down, and the basin is vented back into the building's venting system rather than left open in the basement. Ontario Building Code Part 7 treats the basin as part of the sanitary drainage system for exactly that reason. An unvented basin pushes air and odour past the cover every time the pump runs, and it will not fill or empty the way it should.

Discharge is normally 2 inch, because an ejector is built to pass 2 inch solids and anything smaller defeats the point of choosing one. Above the basin we want a check valve so the column of water does not fall back in, a full-port ball or gate valve above that to isolate the line, and a union or quick-disconnect so the pump can come out without a saw. We are particular about that last fitting because of how many pumps we have cut out of a glued-solid discharge.

A high-water alarm float, set above the pump's start level, costs very little and is the difference between a service call and a wet finished basement. On a commercial basin, or anything serving more than one washroom, it should report somewhere a person will actually hear it rather than to a buzzer in an empty utility room.

A standard sewage ejector passes solids through whole on an open impeller. For a basement bathroom with a toilet it is the default, and it is the most forgiving of the three options when something goes down the line that should not have.

A grinder pump macerates waste into a slurry and pushes it through a smaller discharge, commonly 1-1/4 or 1-1/2 inch, at considerably higher head. It earns its place where the discharge has a long horizontal run or a serious lift, or where a small-diameter route is the only one available. It costs more, draws more current, and the cutter assembly is a wear part. It is not permission to flush things you otherwise would not.

A macerating up-flush unit, the type that sits behind the toilet, is the retrofit answer when the floor cannot be opened: a slab poured over a slab, a heritage floor, or a budget that will not carry excavation and concrete. The trade-offs are real. The unit is in the room with you, so you hear it. It serves a limited number of fixtures, its cutter is small and stops on anything fibrous, and when it fails there is no gravity fallback behind it. We install them where they make sense and say plainly where they do not.

Impellers jam on the same short list every time, and wipes lead it. They do not break apart, they wrap around the impeller and the shaft, and once one is caught it catches the next. Grease is slower and quieter: it congeals on the basin wall and coats the float, and a float that cannot swing is a pump that never starts.

Basins also need opening occasionally. A pump that has run for years without anyone lifting the lid is a pump nobody has inspected, and the parts that fail first, the float, the check valve flapper and the alarm, are all things you find by looking.

Then there is access, which gets designed out more often than you would think. We have found basin lids under a tile floor and behind a wall of built-in cabinetry. When that pump fails, and it will, getting to it costs more than the pump does. Leave the cover reachable and leave headroom above it to lift the pump straight out.

• Wipes of every description, including the flushable kind
• Tampons, applicators, cotton pads and paper towel
• Dental floss and hair, which bind around the shaft
• Congealed grease coating the basin and the float
• Cat litter and construction debris washed down during renovations
• Anything rigid dropped into a basin left uncovered during work