Hello, and thanks in advance for all of your helpful advice. I am an inexperienced plumber ( in advance of my terminology questions I may have ).

I am looking to replace a toilet in a commercial building with a mop sink. I would like to drain the sink directly into the toilet drain.

1. is this allowable
2. what fittings would I need to accomplish this

There is a sink that was removed from the space next to the toilet as well if that is at all helpful.

Thanks again!

Hi Kiasersosa

You will need to tear open the floor and install a PTRAP for the mop sink. Here, toilets have integral traps that are above the floor, so to install a mop sink you'll need to install a PTRAP below the floor and then lead the drain into the new mop sink to finish the job. The vent for the toilet can act as the mop sink vent, no problem.

The new mop sink faucet will need to have proper backing installed behind the wall and the mop sink faucet will need to have a vacuum breaker (backflow protection) on it.

Water proof board is also required around the area of the mop sink (how high/wide depends on code in your area).

Mark

Quote:

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Originally Posted by massplumber2008

Hi Kiasersosa

You will need to tear open the floor and install a PTRAP for the mop sink. Here, toilets have integral traps that are above the floor, so to install a mop sink you'll need to install a PTRAP below the floor and then lead the drain into the new mop sink to finish the job. The vent for the toilet can act as the mop sink vent, no problem.

The new mop sink faucet will need to have proper backing installed behind the wall and the mop sink faucet will need to have a vacuum breaker (backflow protection) on it.

Water proof board is also required around the area of the mop sink (how high/wide depends on code in your area)



Mark

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Yes I was concerned this was going to be the answer. Are there any mop sinks that are raised just high enough to have an integrated p trap?

No, the PTRAP must be installed directly under the mop sink... cannot install the PTRAP above the floor for a mop sink as it would negate the contribution of the drain vent.

Quote:

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Originally Posted by massplumber2008

No, the PTRAP must be installed directly under the mop sink...cannot install the PTRAP above the floor for a mop sink as it would negate the contribution of the drain vent.

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Thanks so much for your help! Looks like its back to the concrete saw for me.