Backwater Valves

[Glennman CBO]

Our city manager has laid out a rule that all DWV installations in the city require backwter protection (any new construction or repairs that involve the main drain) regardless of where they are in relation to the elevation of the upstream manhole cover. The only out is an elevation survey.

The problem is that they are installing them so that the fixtures that are not affected by the elevation issue are going through the backwater valve (all the drains).

Per the UPC, only the drains that are below the manhole elevation are supposed to go through a backwater valve, and the rest are not. I suppose that this is so that the building drain and sewer have the vent that it needs to flow properly.

I haven't heard of any particular issues with this locally, and I don't know what the IPC says about it. Anyone out there know of any problems with the entire building flowing through a backwater valve, even though it doesn't need to, or is required not to, by code?

Thanks...

 

[vegas paul]

Don't you require an elevation survey on all new construction? Grading plan, horizontal control plan, utility plan, etc? Wouldn't be an issue if you had this info on all new construction. BTW, the UPC prohibits fixtures above the elevation of upstream MH cover from discharging through the backwater valve.

 

[Dr. J]

This is similar to the requirment that where sewage ejectors are required for the lowest fixtures, the upper ones that can drain by gravity must. The issue is that a backwater valve or a sewage ejector is a mechanical device that can and will fail, so it is a bad idea, and against code to run waste water through these things if it does not have to. The IPC is similar.

Reading between the lines, the real problem is probably in additions and repairs to existing structures. Any new project should know the important elevations, and therefore be able to design properly. It sounds like the city utilities people are trying to upgrade building connections to the municipal system. It could be an excessive burden on existing buildings to re-route the upper fixtures to a separate building sewer just to avoid the backwater valve.

 

[Glennman CBO]

I wish we did require everything to be surveyed. It would certainly reduce alot of issues. Some of the plans that are taken in are drawn on someone's kitchen table the night before they submit. Well, that's another issue.

 

[Uncle Bob]

Glennman,

" Our city manager has laid out a rule that all DWV installations in the city require backwter protection (any new construction or repairs that involve the main drain) regardless of where they are in relation to the elevation of the upstream manhole cover."

Sounds like your city manager was eating in his/her favorite cafe when the sewer backed up and some little brown visitors floated by the table; since you chose to put this question in the "Commercial Plumbing Code" section.

I don't know what State you are in or what the requirements are for "amending codes" in your jurisdiction; but, everywhere I am aware of; amendments to adopted codes are required to be voted on and approved by the city's governing body (not the city manager); and, your city manager would find his/her behind in a sling. Sounds like your city manager is having a hissy fit; and needs to be reined in.

As a Building Official; before I initiated any such requirement; I would write up a code change proposal and present it to the governing body; accompanied by the specific code requirement; along with any information I gleened from other reliable sources conserning this code change.

When the city manager asks you why you did that; explain that you were just carrying out their orders in accordance with legal requirements (of course you might want to dust off your resume and check the jobs market first).

Anyway, back to your problem.

2006/2009 IPC, Section 715 Backwater valves

715.1 Sewage backflow. Where the flood level rims of plumbing fixtures are below the elevation of the manhole cover of the next upstream manhole in the public sewer, such fixtures shall be protected by a backwater valve installed in the building drain, branch of the building drain or horizontal branch serving such fixtures.

Plumbing fixtures having flood level rims above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not discharge through a backwater valve.

Backwater valves are really bad plumbing fittings. They are mechanical (have moving parts) and prone to failure; and, are made up of obstructions that snag solids and semi-solids; and where the service plumber is not aware they are there, can be destroyed by the drain cleaning machine; and cause all kinds of problems. That is why they are only allowed for specific fixtures; and not allowed on the others.

Probably not what you needed; but, I hope this helps some.

Uncle Bob

 

[mtlogcabin]

Our public works department with the approval of the city council has adopted "design standards" that exceed the plumbing code. ( backflow preventers, grease traps, oil sand seperators) It was done this way because the state does not allow us to locally ammend the building codes.

Agree with others installation BWV on all DW is a bad idea and not code compliant.

 

[Glennman CBO]

#1, I already know that the way they are installing them is not code compliant.

#2, I know that the city manager is overstepping his bounds.

#3, I know I should have posted this on the residential plumbing discussion. Actually, when I went to find it this morning, I looked under residential plumbing and thought someone removed it (he, he).

#4, The city manager is retiring sometime next June or July. If I become the BO, this will definately be revisited.

And finally, we should be requiring elevations anyway.

 

[peach]

They are sometimes installed when there is a combined sewer (not that they work, if the storm water comes in upstream of the sanitary)... but here, everything is eventually "combined".

 

[Glennman CBO]

Yea, that's what I hear when I separate my food on my plate..."it's all going to be combined anyway".