Need to unclog toilet water supply

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Well-known member
Mar 17, 2005
Payson AZ
Somewhere in the water supply line to the toilet there's a clog, probably from AZ minerals.  I'm getting just a trickle of water.  Is there a way to unclog it and clean the mineral deposits out of the system without taking the system apart?  Someone suggested pouring vinegar into the fresh water line.  I assume I'd open lines and release all water pressure before pouring the vinegar into the system.  Should I use straight vinegar or diluted?  Is there a way to get it to feed through the whole system without putting vinegar in the fresh water tank?  Or would that be preferable.  I don't use the fresh water for drinking or cooking, but I don't want to damage anything.  Should I leave it soaking for several days?  I won't be using the MH from 12/23 to 1/9 or 10, so I guess that would be a good time to do this.

I hope at Moab this spring somebody could give a demo on how to take these systems apart for maintenance.  Someone has mentioned cleaning the minerals out of their water system at least annually.


I don;t know about AZ minerals, but I do know the place of greatest constriction in an RV toilet is either the valve pedal or the vacuum breaker.  My first suspect would be the vacuum breaker, which can often be removed easily without dismantling the whole toilet, depending on the model. 

Another test would be to turn off the water pressure, disconnect the inlet hose to the toilet, get a bucket and have someone turn on the water for a moment to see if there is water flow.  That should determine of the toilet has an embolism {g}  .....blockage.

I have always triple filtered the water coming into my coach to prevent sand, rust particles or other matter from getting into my plumbing.  You can get filter systems designed for "all house" residential use at Lowes where two filters are used at the inlet. A third filter is used for drinking water.
Sounds to me as though the valve is either damaged or clogged with sand/minerals.  Try the hose-in-the-bucket test that Steve suggests - it's the easy way to isolate the problem. If the hose runs fine into the bucket, disassemble the valve.  Depending on make and model, there may be a rebuild kit for the valve; others you just replace. But chances are a clean out will do the trick.
It would be very unusual to get a mineral build-up in a cold water line to the toilet. I agree with the first two. Make sure of what the problem is, first.

Do you get a good flow from the spray faucet next to the toilet?  If yes the restriction is probably in the peddle valve assembly as suggested.
Forgot to mention, I did the hose in bucket thing, and there's no pressure before the valve.  Also, the spray hose barely trickles as well.  Now I will look for the vacuum breaker.


If you removed the main water line from the toilet and there was no flow, disregard the vacuum breaker - it's part of the toilet and you've already narrowed it down to some problem with the supply line. If you've got good flow at other faucets, then you've narrowed it down further to the toilet feed line. Otherwise, you may have a problem with your pump, clogged filters, crimped/kinked main water line. If you're running off city water, make sure your white water hose isn't kinked somewhere and check for a clogged screen (if present) on it.
Karl:? Bathroom sink faucet works fine. All other faucets work ok.? I don't use the pump and fresh water tank, but I filled some water in the tank and ran the pump.? Still poor pressure in the toilet.? Must be the toilet feed line.? There isn't any visible kink.? Could there be a kink in the spray hose that affects the water to the toilet?? Something must have dislodged on the way down from OR to AZ in September.?

Could there be a kink in the spray hose that affects the water to the toilet?

You can run your hand along the spray hose up to the vacuum breaker, which supplies the spray hose using a Y connection.  However the vacuum breaker is downline from the valve, so if you don't have pressure coming into the toilet at the inlet hose, it's unlikely the spray hose is at fault.

You need to work your way back from the toilet inlet hose.   

I would disconnect the inlet hose, put it in a bucket, and have a friend apply air pressure at the RV water inlet.  Expect a blast of water and perhaps the embolism that is clogging the line.
Steve:  I'll do that in the morning.  I've emailed myself this topic for my file.  I am also going to learn to do some regular preventive maintenance on the water system to prevent this.


IMO the best preventative meaintenance is to install dual filters at the waer inlet of the RV.  They may become blocked but it's easier and cheaper to replace filter cartridges than to dismantle plumbing.
Steve:  Agreed on the filters.  Just did that this past September, so I have 3 years of clogging to clean out.


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