RO Storage Tank Takes a Long Time to Fill. Please Help!
Written by: Gene Fitzgerald // Last Updated: Mar 4, 2023
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You’ve just got yourself a brand spanking new, state-of-the-art, under-the-sink reverse osmosis system. How exciting!
I’ll bet you can’t wait to taste the purified water. You open the faucet, and…. Nothing. What? Why?
Checking the tank, you realize it’s very light and doesn’t have any water in it. What’s taking so long?
Let’s see!
Contents
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Key Takeaways
- RO storage tanks, in general, do take at least 2-4 hours to fill, depending on several factors such as their size.
- If your RO tank has not filled even after several hours, it may be due to:
- A closed or partially closed feed water valve or tank valve.
- Your home water pressure being too low.
- Clogged membranes or filters.
- Kinks in the tubing.
- An over or under-pressured tank bladder.
- Air in the RO system.
- Improper sizing of your RO system or storage tank.
Why Does My RO Storage Tank Take a Long Time to Fill?
First things first, an RO storage tank does take a long time to fill! Especially if it’s a big one. 2 to 4 hours minimum can be about standard, depending on factors such as the flow rate of your home water. But, if you have just had it installed, give it a bit of time to fill itself up before you try to use it.
If it has been several hours and still nothing, then there may be an issue, so go through this list to see if you can pinpoint what that is.
Partially Closed Feed Water Valve
Check your feed water valve. Is it all the way on? Ensure that it is open all the way, so an adequate amount of water is flowing to your RO system.
Partially Closed Tank Valve
Is the valve on the storage tank open? Double check. If not, water will not be accessing the tank. Ensure the tank valve is open all the way.
Your Home’s Water Pressure Is Too Low
Your home’s feed water should have a minimum pressure of 40 psi in order for your reverse osmosis unit to function correctly. Check the psi of your feed water using a pressure gauge to make sure it is at least this amount. You can install a booster pump if the pressure is too low.
One or More Clogged Filter Stages
If your RO system is not new, are you on track with filter maintenance and replacement? Clogged pre-filters or RO membranes will reduce the ability of the tank to fill with filtered water.
A Kink in the Tubing
Water flow and pressure can be restricted by kinks or unnecessary dips in your lines and tubing. Check the system carefully to see if there are any that need straightening out.
Over-Pressurized Tank Bladder
If your RO storage tank pressure is too high, then the level of water it can store will be diminished. You will need to disconnect the tank, empty it completely and adjust the tank pressure to 6-8 psi.
Further Reading:
Air in the System
After filter replacement, air might have become stuck in the RO system, creating an airlock whereby water won’t flow. To release the airlock, you will need to close the storage tank valve and open the RO faucet to drain. You can tilt the system if you need to.
Your RO System Is Too Small or the Storage Tank Too Large
If your RO system is too small or your RO storage tank is too large, then the storage tank backpressure may affect its ability to fill.
How Long Does It Take a Reverse Osmosis Water Storage Tank to Fill on Average?
On average, an RO storage tank can take at least 2 to 4 hours to fill completely. This depends on the tank’s overall size and your water pressure and flow rate, of course, but several hours is a safe bet.
If you have any questions about why your RO storage tank takes a long time to fill please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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