Sewer pump for the house

FirstTimeBuilder7 · Feb 02, 2024 11:27 pm

We are told by a builder that we need to have a sewer pump because the sewer connection invert level is too shallow for our land which prevents having enough drop for gravity to work. Keen to know if anyone has any experience with sewer pumps? What brand, size etc we need to consider? And how much it costed you? The builder says cost of pump, tank, pit and all plubing will be more than $10k

building-expert · Feb 04, 2024 1:54 pm

These are the issues to be picked up and resolved at your building design stage. If indeed the pit and the pump was required it should have been specified and detailed on your house/land drawing. has your house started? If not it may not be too late to adjust your house levels.

I have recently had sewerage cutter pump installed (Davey pump about $1800)+ pit $1000 + double that for the plumber+ electrical power point.
At another location I have effluent pump $ 350 + existing pit, all works fine.
I would have some serious questions for your building designer.

FirstTimeBuilder7 · Feb 05, 2024 1:01 pm

We did our design independently and got our DA a few years ago. The designer picked the level of the mid-point of the block and set it as ground level to minimise cutback and infill on front and rear side of the block. That means the builder has cut back 500mm from the front of the block where sewer connection is. And we realised sewer invert level is too shallow only last week when it was exposed and plumber cane on site.

building-expert · Feb 05, 2024 2:34 pm

Your designer should have checked sewer inlet level before setting house slab level, and also legal point of discharge for the stormwater, so it should not have come as a surprise to you. Maybe the money you saved on foregoing slab at a higher level is now the money you have to spend on drainage.

FirstTimeBuilder7 · Feb 05, 2024 3:05 pm

Thanks for the advice. Can I ask if you have had any experience with sewer pressure pumps/tanks? Which brand to chose and reliability of them? We are given the option of Graf sewer tank plus Xylem grinder pumps

building-expert · Feb 06, 2024 11:22 am

I prefer Davey pumps because it is a good Australian brand that has been around forever. If you log on their web site you will find the details you need. Other than having Davey pumps in two locations working perfectly I don't have experience with other pumps.

FirstTimeBuilder7 · Feb 06, 2024 4:11 pm

How would you approach the issue with the designer given its too late and the construction is underway. In summary, we need to pay $15k extra and will always be relying on a sewer pump for the whole house because of this

building-expert · Feb 06, 2024 5:00 pm

The best is to write to them describing the problem and the cost and asking why have design levels have not been set to allow for gravity sewer discharge.
What is the difference in levels that would make gravity sewer work?

FirstTimeBuilder7 · Feb 06, 2024 10:39 pm

The level needed to be about 500mm higher. I had a chat to him and pointed out the issue but he replied he is not a plumber and its not up to designer to decide on how high the level should be and if he had set the level higher the council would not approve the current design due to other variations we had. But I am still not convinced...

building-expert · Feb 07, 2024 3:18 pm

That's a lame answer. It does not cut it. Setting the levels is the design issue.
The fundamental job of the building designer is to review all the properties of the land and services before setting FFL. If it were true why didn't you know about it? Why wasn't there a notation on the drawings or in the specification that the current design does not allow for gravity sewer discharge. Sure the designer is not a plumber but why did not designer ask the structural engineer to design drainage?
If it were done properly then you would either have the opportunity to take the mater with the council ( remember nearly everything is negotiable) or the engineer would have designed drainage and specified the required pump. Who is now going to do that? Your builder?
Graf sewer tank is a septic tank, you don't need that (unless your land is un sewered), all you need is a plastic pit with a automatic pump in it.
It look to me they didn't know or didn't care.

building-expert · Feb 07, 2024 3:19 pm

what state are you in?

FirstTimeBuilder7 · Feb 07, 2024 8:52 pm