Minimum depth of domestic sewer

[JDE]

I am building an art studio with a tiolet and sink. It is to be off one end of the house. Problem is the sewer drains to the opposite end of the house. The nearest pick up point is 12.6m away and only 360mm to the top of pipe below ground level. While I understand I will need to go out through the wall rather than under the slab footings to get enough fall. Is there actually a legal depth the pipe must be below the surface at the shallow end? I cannot raise the soil level as it is set by the house floor level. Does anyone know?

Thanks James 

[MitchellMc]

Hi @JDE. Many thanks for your question.

I am not aware of a minimum depth requirement, nor can I find documentation to verify but you would need to follow a 1:60 fall rate over the distance.

I'm confident members will be able to assist with your sewer question. Let me invite a former plumber @LePallet for you, he might like to kick off the discussion.

Thanks again,

Mitchell

[JDE]

Thanks Mitchell 

Ive got the fall covered and it will be under garden bed and lawn at the back of house. Weve had 2 plumbers have initial look for quoting. I cannot find any actual rules in NSW. But second plumber was suggesting a minimum of 300mm at studio end which would require an additional 30plus meters of trench/pipe.

James 

[redracer01 · Accepted solution]

Hello @JDE 

Have you thought about using a Saniflo pump? This should sort out any fall issues you have, the Saniflo pumps have a 5 meter vertical/head capability and can pump at a slope for 50 meters. You can check out the specifications on their website and see which pump is right for you. This will greatly reduce your plumbing bill  and offer you a better option to digging.

Cheers,

Red

[JDE]

Redracer01 thanks l had forgotten about these. Our council actual uses a commercial version of these in some areas of town. We had one at our last house. I wasnt aware there was a smaller version available.  I have already poured the slab so pipes will have to come out back wall. I have enough fall on the pipe but it will only be 100mm below ground level at the high end. I'll have to check the rules with council but at least now you have given me a backup plan. Thanks James