You press the tap and nothing comes out, or the tank takes hours to fill. An RO not giving water is one of the most common complaints we get. In many cases the cause is simple. This guide walks through the likely reasons in the order a technician would check them.
Start with these quick checks
Before calling for a repair, check these four things. They solve a surprising number of cases.
- Is the inlet valve open? Look for the small valve where the purifier connects to the water line. It is sometimes closed by mistake during cleaning.
- Is there water in the line? Open the nearest kitchen tap. If the building tank is empty or pressure is low, the purifier cannot work.
- Is the purifier powered? Check that the plug is in and the socket works. Look for indicator lights.
- Is the tank tap closed? On models with a tank valve, make sure it is open.
Common causes and their fixes
Choked sediment or carbon filters
The most common cause. Dirty water clogs the pre-filters until hardly any water reaches the pump. The fix is to replace the filters. If they were changed recently and choked again quickly, your water may need an extra pre-filter. See RO filter replacement.
Blocked or scaled RO membrane
Hard water leaves scale on the membrane, and output drops to a trickle. A technician can test the membrane's flow and TDS rejection and replace it if needed.
Faulty solenoid valve
The solenoid valve opens when the pump runs and closes when it stops. If it sticks shut, no water enters the system even though everything else is fine.
Failed pump or adaptor (SMPS)
If the purifier is silent and shows no lights, the adaptor may have failed. If the pump hums but does not build pressure, the pump head may be worn.
Low-pressure or high-pressure switch
The low-pressure switch stops the pump when input pressure drops. A faulty switch can keep the pump off even when pressure is normal. A faulty high-pressure switch can stop the pump too early.
Float valve or tank problem
In purifiers with an internal tank, a stuck float valve can stop filling. An air bladder tank that has lost pressure fills but will not push water out to the tap.
Air lock after filter changes
After new filters are fitted, trapped air can stop flow for a while. Running the purifier for several minutes usually clears it.
When to stop and call a technician
- The pump runs but no water comes out after a few minutes. Running a pump dry damages it.
- You see a burning smell or a hot adaptor.
- Water is leaking along with the no-water problem. Read why your RO is leaking.
- The filters were changed recently and the problem came back.
How we fix it
Our technician tests input pressure, each filter stage, the membrane, valves and electricals, then tells you what has failed and what it costs before starting work. Common parts are carried on the visit. Book an RO repair or see our full list of common RO problems and solutions.
Frequently asked questions
My RO makes a sound but gives no water. What is wrong?
If the pump is running but no water comes out, the most common causes are choked filters, a blocked membrane or a faulty solenoid valve. Switch the purifier off to protect the pump and book a check.
Water comes from the tap but the RO gives nothing. Why?
Check the inlet valve feeding the purifier first. If it is open, low pressure, a choked sediment filter or a stuck solenoid valve are likely.
Can low water pressure stop an RO?
Yes. Most domestic RO purifiers have a low-pressure switch that stops the pump when input pressure is too low. This is common in upper floors when the overhead tank runs low.
Need help with your purifier?
Share your purifier brand and the problem. We will call back with the next available slot.
