Low Pressure With a Home RO Water System

Concerns regarding water quality and purity lead homeowners to install reverse osmosis water filter systems.

Reverse Osmosis System

Find out the cause of low water pressure in your reverse osmosis system.
These systems remove contaminants from tap water through the filters, producing high-quality drinking water. Whether you rely on well or municipal water, reverse osmosis systems provide added assurance that your water is safe for consumption. Basic troubleshooting can usually identify the cause of low pressure in a reverse osmosis system.

No matter the brand name, reverse osmosis systems share the same basic components. These include a cold water line valve with a tube connecting to the reverse osmosis system's prefilter, the system's water source. Water enters the prefilter, generally a sediment filter for salt and dirt removal. Some systems also have carbon filters for chlorine removal. The system's center is the membrane, usually a wound spiral consisting of either cellulose tri-acetate, which tolerates chlorine, or thin film material, which does not tolerate it. After leaving the prefilter, water enters a storage tank holding up to 2.5 gallons and then goes through the postfilter. This consists of carbon in either block or granule form, which removes any remaining odors from the water. Water from the reverse osmosis system flows through a special faucet generally installed on a kitchen sink.

Automatic Shut-Off Valve

For conservation purposes, reverse osmosis systems include an automatic shutoff valve. This prevents water from entering the membrane if the storage tank is full, stopping the cycle. When this valve operates, it also prevents water flowing into the drain. If you draw water from the reverse osmosis faucet, tank pressure drops, causing this valve to open, permitting water to enter the membrane. Any contaminants in the wastewater then head down the drain.

Low Pressure

The primary cause of low pressure in the system is air pressure in the storage tank. To rectify this problem, empty water from the tank and, using an air pressure gauge, make sure that the air pressure is between 8 to 10 pounds per square inch. Check all appropriate valves to make sure they are open and not stuck.

Other Causes

If you check the air pressure in the tank and it does not appear to be the culprit causing low pressure, make sure the filters are clear and the membrane is unclogged. See if any of the system's tubes are kinked. Replace the filters regularly according to the manufacturer's instructions, generally once or twice a year. If the low water pressure continues, you may have to install a booster pump in the system.

About the Author

Jane Meggitt has been a writer for more than 20 years. In addition to reporting for a major newspaper chain, she has been published in "Horse News," "Suburban Classic," "Hoof Beats," "Equine Journal" and other publications. She has a Bachelor of Arts in English from New York University and an Associate of Arts from the American Academy of Dramatics Arts, New York City.