Reverse Osmosis Filters
Questions & Answers

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A few months back, we bought an one R.O. system from Costo, Taiwan  and installed it. Well, it seems that you get what you pay for, as after being connected for 2 days one of the factory-installed joints (between stages) broke loose overnight and proceeded to pour hundreds of gallons of water into our under-sink cabinet and consequently into our finished basement, causing over NT$11,000 in damage.

So I went through each joint, tightened them all, and put the unit back into service. A month went by, and a different joint failed while we were at work, again dumping lots of water into our basement. My analysis of the failed joint indicated that even though the fitting was tightened down securely, the tube was not held securely and blew out. It seems as if the joints and fittings are of really poor quality, and will never be up to the task they're required to do. Can you help ?
Jack Wong, Taipei

Dear Jack: Instead of trying to fix every joint and tighten every fitting yourself, you're probably better off getting a new, better quality system. Because the problem is not that the fittings were not tightened enough; the problem is, as you said, that the parts are of very poor quality (can not seal completely, crack under pressure...). Since the system has broken twice already, I'd doubt the system's integrity and stability. If the system is overall poor quality, changing the parts will not solve the problem -- you're likely to get new leakage, blockage down the road, lots of hassle & costs. I say use it for as long as you can, if it breaks again, then do away with it and get a good quality system.

Generally, we don't recommend buying r.o. systems from mass merchandisers (B&Q, COSTCO, CARREFOUR) because the systems they carry usually are mass-assembled and imported. The materials used are often cheaper and the systems not individually tested for leakage & pressure endurance. They'll work fine for a couple of years, then problems often surface afterwards. Good Luck!

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We learned it the painful way that when it comes to water systems, a good quality system is WELL worth its value! We have recently bought an economical R.O. System. After installation, it seems to work fine. But one morning we woke up to find that our first floor was flooded with water. After searching, we found that one of the R.O. system's housing has burst and caused all this.
We called them up they said our water line pressure is too high. But we checked our pressure it is around 85 psi. It seems to be still in the operational range. What can we do?
Maria Thompson

Dear Maria: 80 psi is strong pressure, but it shouldn't have caused the bursting because a good reverse osmosis housings should be able to withstand up to 100 psi. The minimum you need to do is to replace the 3 pre-filter housings (and their caps) with better quality ones, preferably double o'ring housings they've gone thru endurance testing. We recommend "double o'ring housings"(Top one of Taiwan Water Purification Manufacturers)- known to have the highest pressure endurance, Taiwan made & NSF approved.

I have bought a three stage R.O.. system from a different company. I live in Taipei, it is very hot in the summer.  I installed the RO system in the garage. There is a water softener in front of the RO system. We notice a distinct Plastic smell and taste in our RO water. Please help with any suggestions you may have. I examined our system and have found that most parts on this system are made in China. Do we need a different type of tubing or housings? Could the temperature in the Garage have damaged the RO membrane and/or made the charcoal filters less effective. This system was installed new in November '02.
Jerry Lin

Dear Jerry: The 3-stage reverse osmosis system is of an older technology. Their filtering ability is not as thorough as the new 5-stage systems. The membranes used on the 3-stage reverse osmosis systems are the CTA type, which give a contaminant rejection rate of about 80%, while the TFC type membranes used on 5-stage systems give 90%-98% rejection rate. CTA membranes also tend to break down when the input water's pH is either too high or too low. Because there're only 3 stages of filtration, each filter has to work harder, therefore deplete a lot sooner than filters on a 5-stage system. So if your tap water's quality is bad & demands heavy filtration, then the prefilers & membrane on your 3-stage system will need frequent changing, or they may fail prematurely, causing the weird tastes in the water that you're experiencing.

The distinct "plastic smell" could also come from the storage tank's rubber bladder, or from the plastic housings & tubing, since you mentioned that the parts are made in China -- all China made parts have not been tested for "material extraction" by NSF. These tests are done to make sure that the system's components do not release substances into the product water. So yeah, it's possible that the plastic parts on your RO system is leaching the plastic smell into the water under high temperature.

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