Reverse osmosis systems remove the most contaminants of any available under-sink filters. These are the sorts Poor taste and unpleasant smells are removed, as well as almost all chlorine, heavy metals such as lead, and bacteria and parasitic cysts. Additional stages can be added to the filter in order to add additional effects. Optional additions include a UV filtering stage, and an AK carbon filter. The UV filter can cause problems, as it will heat the water when it is not flowing through the system. Reverse Osmosis systems also tend to strip minerals that can be an important and healthy addition to your drinking water, and can also make the water slightly acidic, affecting the taste. An optional mineral filter adds those minerals back into the water, with the additional effect of balancing the pH.
The process of reverse osmosis takes time, and produces water at a slow rate. As a result, these sorts of systems require a holding tank that the filters fill, and then supplies the faucet. This can result in low water pressure, particularly in areas where the water supply has a low pressure (below 45 psi is what the manufacturer says). A pump can be added to the system to increase the pressure to the faucet.
All these additional filters, and the complexity of the base system, can seem overwhelming. However, the filter comes with all the necessary equipment to install it, including wrenches, Teflon tape, and spare O-rings. Pipes are color coded to make it easier to understand what goes where, the manufacturer has also put a video on YouTube that shows how to install the system. However, if you’re not familiar at all with basic plumbing systems, it can be a good idea to get a plumber to install the filter for you. Leaks with the system can create a lot of water, and it can go unnoticed as it is under the sink. One additional upgrade iSpring offers is an alarm that will go off, something like a smoke alarm, if there is a leak and collecting water.
The unit comes with a faucet that the filter feeds, allowing you to choose when to use filtered water and lengthen the life of the filters. However, another hole has to be added to mount the faucet. Some sinks do come with a hole for a filter faucet, soap dispenser, or that sort of thing. The standard size for these things is 1”, while the size of the mounting that comes with the filter is 1/2”. Mounting the 1/2” faucet in the 1” hole does not work well, and can cause problems. The manufacturer does sell a 1” faucet that works with this system, but it has to be bought separately.
The iSpring filter comes with a 30-day money back guarantee, and a 1-year warranty for parts and manufacture. There is also a helpline that can be called, and that is usually pretty responsive and helpful. Overall, this filter is cheaper than many comparable systems and does a great job.