A reverse osmosis (ro) system filters water through a semi-permeable membrane and through several macro-porous filters. Typically, a ro system creates one gallon of good drinkable water to four gallons of waste water. Although this sounds like a lot of waste water, it’s very minimal and hardly noticeable when you look at your water bill.
The most common call we get when troubleshooting a reverse osmosis system is people reporting that the flow of water out of the faucet has weakened, or tremendously slowed down. If you have ever noticed that you have a problem getting a gallon of water or even a few cups of water then there is an issue with your system. Several things can cause this problem and hopefully after reading this you should be able to pin point your problem. There are four things that affect water flow; check valve, flow restrictor, clogged filters, or burst or under-inflated ro tank. Keep in mind that this article only covers water flow issues and not all reverse osmosis troubleshooting problems.
A reverse osmosis tank has an internal bladder or diaphragm usually made of butyl rubber. A problem that you may have experienced with a reverse osmosis tank is when you open the water faucet and get a burst of pressure; which is rapidly followed by very low pressure flow. Another symptom that can confirm that the issue is tank related is seeing if the tank is full. If it is, than you can confirm that the tank is the source of your problem. This is caused over time when the bladder is damaged or loses pressure due to a leaky air nozzle valve. Pressure loss can simply be fixed by properly adding more pressure to the tank but the problem may occur again over time. Proper inflation of a tank is 6-8 psi when empty. Unfortunately, a damaged bladder is non-repairable and must be replaced completely
If, however, you open the water faucet and there is an absence of that burst of water pressure then you may have a different issue. To confirm the problem, check the system’s waste line and the tank. You may find that the water continuously drains (at its normal rate) and will not stop and that the tank is empty. A reverse osmosis water check valve allows water to flow only one way and forces water to fill the tank. If the check valve is damaged, it can cause the water to continuously flow from the tank and through the check valve. Replacing the check valve will stop the water back flowing to the drain line.
On the other hand, if the waste water drains at a much stronger or near full force then the problem is more likely that the flow restrictor is damaged. A flow restrictor slows the amount of water that goes to the drain and puts back pressure on the tfc ro membrane to force water past the check valve. You will also find that the tank is empty.
Lastly, clogged filters can cause water to stop flow completely or greatly diminish the flow. By simply replacing your filters within the manufacturer’s recommended time frame, you can eliminate this problem. Just because filters may look clean doesn’t mean that they have not been used to their limits. Replace your water filters regularly and you’ll find that most of your clogging issues can be solved. However, I find the clogged filters are usually the least common reason why the faucet water flow is limited or completely stopped.
The solution is almost always going to be in this guide. The key is locating it and hopefully we have done that for you. The parts used to fix your ro system are merely a few dollars but doing it yourself is self-rewarding. When in doubt, feel free to call a water dealer to get some advice. You’ll be surprised how some helpful some dealers can be.