Is the drain line on my water filter making noise because it's too low?
July 16, 2016 4:52 PM
I have a reverse osmosis water filter system with an air gap faucet. It's a Watts Premier system with an air gap type faucet. When the tank is filling up there is a constant gurgling noise. Is this just because it's a new installation or is my drain line too long?
Closing the stopper on the drain reduces the noise somewhat and putting my finger over the air gap hole on the faucet prevents it from making the gurgling noise so it's almost certainly air in the drain line causing the noise with air being sucked through the hole in the back of the faucet. The advice I read online was to shorten the drain line so there's no upward loop, so I took it out and cut the line shorter, but is it still too long or will the noise go away after a week like other sites online said?
Pictures of the drain line can be seen here.
Recording of the noise in case it's helpful. There are three recordings as follows
- Drain open
- Drain closed
- Finger over faucet hole
When I cover the hole on the back of the faucet it still sounds like there's air in the system but it's not as loud. When the tank is full (after about 3 hours) the noise stops, but once a certain amount of water is used the tank starts to fill again and the noise returns. Thanks for any advice!
Closing the stopper on the drain reduces the noise somewhat and putting my finger over the air gap hole on the faucet prevents it from making the gurgling noise so it's almost certainly air in the drain line causing the noise with air being sucked through the hole in the back of the faucet. The advice I read online was to shorten the drain line so there's no upward loop, so I took it out and cut the line shorter, but is it still too long or will the noise go away after a week like other sites online said?
Pictures of the drain line can be seen here.
Recording of the noise in case it's helpful. There are three recordings as follows
- Drain open
- Drain closed
- Finger over faucet hole
When I cover the hole on the back of the faucet it still sounds like there's air in the system but it's not as loud. When the tank is full (after about 3 hours) the noise stops, but once a certain amount of water is used the tank starts to fill again and the noise returns. Thanks for any advice!
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A reverse osmosis filter creates wastewater, water carrying off unwanted stuff, as a side effect of the filtering process. That water has to go somewhere. When our system is filtering, a moderate stream of wastewater falls into the utility sink (that's our air gap), slowing to a trickle as the tank fills.
Your system appears to put its wastewater up into the tap where it is air gapped, as you note. This prevents potential backflow into the filter. The air hole is a necessary component to this.
Since there's a break in the line letting air in, and gravity pulls the water down towards the sink's drain, a gurgling sound would seem to be a natural side effect. I can not think of a reason that this noise would "go away" after a week, other than you might just get used to it. Your system will continue to generate wastewater whenever it is actively filtering and filling the tank.
If the noise is objectionable, you might see if alternate arrangements to get rid of the wastewater are available and allowed by code.
posted by jgreco at 2:38 PM on July 17, 2016