Thread: Dishwasher water supply protection

Referring to IRC 2006 page 435 P2717.1 the water supply shall be protected by an air gap or integral backflow preventer.
I was wondering if this meant just the DW or for whole house, if for just the dishwasher I do not believe I have ever inspected a home new or used that had this protection.????

Len Couey
Kerrville Tx

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Originally Posted by Len Couey

Referring to IRC 2006 page 435 P2717.1 the water supply shall be protected by an air gap or integral backflow preventer.
I was wondering if this meant just the DW or for whole house, if for just the dishwasher I do not believe I have ever inspected a home new or used that had this protection.????

Len Couey
Kerrville Tx

LC:

SECTION P2717
DISHWASHING MACHINES

P2717.1 Protection of water supply.

The water supply for

dishwashers shall be protected by an air gap or integral
backflow preventer.

Residential or domestic dishwashers must conform to
ASSE 1006. This standard includes protection of the
potable water supply against backflow. Units conforming
to this standard possess backflow protection consisting
of an internal, integral backflow prevention device.
Where a unit does not meet this standard,
protection must be provided by means of an air gap.
Section P2902.3.1 mandates an air gap.

P2902.3.1Air gaps.

Air gaps shall comply withASMEA112.1.2

and air gap fittings shall complywithASMEA112.1.3. The inimum ir
gap shall be measured vertically from the lowest end of a
water supply outlet to the flood level rim of the fixture or receptor
into which such potable water outlets discharge. The minimum
required air gap shall be twice the diameter of the effective opening
of the outlet, but in no case less than the values specified in
Table P2902.3.1. An air gap is required at the discharge point of a
relief valve or piping. Air gap devices shall be incorporated in
dishwashing and clothes washing appliances.

"Referring to IRC 2006 page 435 P2717.1 the water supply shall be protected by an air gap or integral back-flow preventer.
I was wondering if this meant just the DW or for whole house, if for just the dishwasher I do not believe I have ever inspected a home new or used that had this protection.????"

The supply line for the DW connects at the bottom of the DW.
After the connection it could be piped to the sides or even the top of the DW. The fill line entering the Dw is above the water level of the DW. This will provide the air gap mentioned.

Many DWs fill from the bottom. This type of DW is required to have a backflow preventer installed on it.
The DW comes from the factory with the backflow preventer already installed.
Since the BF preventer is integral to the DW, you may not see, or recognise it.

I don't know when DWs started having this.

I just hung up with GE appliances who informed me that they used to include integral check valves in their pump systems to prevent backflow but they no longer do. Now they just specify in their installation instructions to use a countertop air gap or route the drain hose in a high loop a minimum of 32" from the floor.

Erin

The OP was about the supply line, yours is about the discharge.
But thanks for posting that information.

Rick
Thank you for pointing that out. My apologies.

Kitchen accessories are available in variety. You may choose water supply in various form for your kitchen. Suit yourself how your kitchen is convenient with the supply of water.

Originally Posted by Galvin

Kitchen accessories are available in variety. You may choose water supply in various form for your kitchen. Suit yourself how your kitchen is convenient with the supply of water.

So, I"m just guessing that English is not your first language?