Sanitary sewer for existing and proposed facility

Question

Sanitary sewer for existing and proposed facility

Bravo8 (Civil/Environmental)

(OP)

8 Sep 20 01:38

I have a project where a proposed building location is on top of an existing sewer lateral from an existing facility. The proposed building location is between the existing facility and the main sanitary line. There is no room to move the proposed building. I recommended to relocate the existing sewer line around the new building, but the client wants to connect the existing sewer line to the new buildings plumbing. Basically run the existing building's sewer through the new plumbing beneath the proposed building. The existing sewer line only supports a floor drain, but I don't think it is a good idea to connect the existing lateral to the new building plumbing system. Are there any Florida state rules or plumbing codes against the client's proposed scenario?

oldestguy (Geotechnical) · Answer 1 · 2020-09-08 19:57:20

As to pressures possibly sitting over the old line, look up what is called "imperfect trench" as devised by old engineers at Iowa. I've used it a few times.

JedClampett (Structural) · Answer 2 · 2020-09-08 20:50:32

As a homeowner with a project looming of digging up about 15 ft. of my floor to replace an deteriorated underground pipe, it makes me wonder how you could maintain the existing pipe.

bimr (Civil/Environmental) · Answer 3 · 2020-09-08 20:55:24

All installation details will be governed by the local code authority and must be approved through one or more inspections.

Not enough information is provided.

What is the condition and age of the existing sewer?
What is the property ownership of the buildings? If there is separate property ownerships, then the joint sewer is probably not acceptable to the local AHJ.
If the size of the property is very small (~7,500 square feet or less) than the joint sewer may be acceptable.

eea (Civil/Environmental) · Answer 4 · 2020-09-09 17:12:25

I would route the existing pipe around the proposed building using 3 manholes. You would likely need to upsize the new pipe since you would be increasing the length of run and holding the upstream and downstream inverts. In Illinois, you would need to pull a permit w/ the IEPA since two or more connections becomes a sewer main, not a private lateral. You could approach the local agency (City or sanitary authority) for the point of connection with your client's lateral and the existing one to become a public sewer, but if they decline it would still become a private main. Either way, you would want to generate a recorded easement for the alignment across your client's parcel. The easement would also be a chance to define where maintenance & private ownership or joint private ownership &/or a public main begins.

GeoEnvGuy (Geotechnical) · Answer 5 · 2020-09-12 04:51:26

Quote (Bravo8)
Are there any Florida state rules or plumbing codes against the client's proposed scenario

Yes and you should review the local jurisdiction sewer design guidelines.

Also a sewer for the existing structure has been sized to meet the requirements of that building. Now the owner proposes to say that the old sewer is big enough to handle the existing structure and a brand new structure required flows combined. I dont think the local building department will let that go unless the existing sewer is a tunnel.

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Sanitary sewer for existing and proposed facility