20 Most Recent Culligan Under Sink Water Filter Questions & Answers

A TDS (total dissolved solids)meter is needed to test the Reverse Osmosis water and compare it to the feed water to determine how much TDS is being removed. Reverse osmosis membranes are designed to remove 80-95% of the TDS in your water supply.

For example: If your water has 500ppm of TDS the minimum TDS removal should be 400ppm leaving 100ppm. If the TDS from the Reverse Osmosis System drops to these levels it is time to change the Membrane.
Typically an RO system will consistently remove 90+% of TDS for many years. The normal lifespan for a membrane can be anywhere from 3-10 years. It all depends on the TDS of your water and your water usage. The higher the TDS the more frequently the membrane needs replacing. The other filters should be replaced every 6 months to keep the quality up and protect the membrane.
A TDS of 1000ppm compared to 100ppm is much more difficult remove to acceptable levels. I like to compare 1000TDS to taking muddy water, forcing it through a filter and getting drinking water. Where 100TDS may be more like a clear glass of water. Consequently a reverse osmosis system on high TDS will be less efficient, less gallons produced and filters will need to be changed more frequently to keep the quality and quantity up.

Culligan Under... | Answered on Mar 10, 2018

Depending on the model of your system here is a link to the manuals for Culligan Units.


Culligan Under... | Answered on Mar 08, 2018

plastic line and fitting are a snap in item
push the line in and at the same time press in the ring at the end of the fitting
that releases the clamping action of the line
make sure that the water is turned off and the pressure in the line is released

Culligan Under... | Answered on Jul 08, 2017

Some RO storage tanks have the capability to change the bladder. Unless the bladder has a hole in it there is no reason to replace it. Air can be added to adjust the pressure. My suggestion is to just change the whole tank with a different style.

Culligan Under... | Answered on Aug 13, 2016

There may be air in the system.

Culligan Under... | Answered on Apr 19, 2016

The softener is not drawing brine during the regeneration cycle. The eductor assembly may be plugged or you may have a bad seal internally. It will keep filling the salt tank if the float assembly is not working properly also causing the salt tank to overflow.

Culligan Under... | Answered on Mar 07, 2016

Well the simplest answer is the gasket isn't seated properly. The standard approach is to remove the cartridge, check for any foreign material (dirt, sand, grit, etc.), rinse with clean water if necessary and reassemble.

Sometimes these cartridge units can be fiddly to get the seals to 'seat' properly so once you're sure that the parts are together nicely then you can use a bit of pressure to tighten them up. They usually need to be fairly tight.

Culligan Under... | Answered on Jun 10, 2015


The terminology is a little bit misleading...

By flushing they mean that you still install all of the filters and then you open the valve and keep it open... in this case if you change everything... for a period of 6 hours....and by that time you will have run the 5 gallons and 2 gallons through for the other two filters...

So.... just install the filters and then just prop open the faucet valve for six hours and you'll be good!!


Culligan Under... | Answered on Jan 27, 2015

The reverse osmosis faucet you have incorporates an AIR GAP to prevent cross contamination to the RO system. The waste water first goes up the to RO faucet AIR GAP and then goes to drain. The "gurgling noise" is the waste water going to drain. Some of these are much noisier than others.

Culligan Under... | Answered on Jan 21, 2015

Normally when it leaks out the weep hole the drain line is plugged under the sink....turn off the ro to where it's not making water, disconnect the drain hose and flush it out....make sure the adapter that's connected to the drain pipe is still lined up with the hole if it was moved the water can't get to the drain.

Culligan Under... | Answered on Sep 25, 2014

After you replace the water filter the alarm needs to be reset. Just take the battery out and reinstall to reset.

Culligan Under... | Answered on Sep 01, 2014

You can get replacement cartridges for all the H series through AC series RO systems on line from several suppliers. I use them and they work just fine.

Culligan Under... | Answered on Aug 24, 2014

Turn the water supply to filter system off, open the faucet to relieve the pressure.
It depends are where it is leaking form. If you just changed the filter it is either not on all way, the o-ring is pinched or missing, or the inlet line, outlet line (or both) were worked loose and are leaking.
Check the feed valve to the filter also. If it is a saddle/ piercing valve it may be leaking. After opening and closing these valves several times the "packing nut" may work loose and the valve leaks. Tighten this very slightly until leak stops. Here is a diagram of a saddle/piercing valve.


The packing nut is right below the T handle as in this picture. There is seal under the packing nut and this is where it can leak from when the nut works loose. AGAIN tighten this very slightly to stop the leak.

Culligan Under... | Answered on Aug 18, 2014

Since unfiltered water went through it for a couple days, I would guess you have mineral build up. If this is the case, be careful about trying to use it. There are certain products you can buy to unclog the pipes. Most will have you pour them down through the pipes connected to the polishing filter. If you can take the pipes apart, I suggest going pipe by pipe to see where the build up is.

Elisa Jed ' http://www.watertectucson.com

Culligan Under... | Answered on Jul 17, 2014

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