So You Want Cleaner Water, Now What?

Maybe you’ve gotten a few too many “boil water” notices from your local utility, maybe you’ve gotten back some water test results that are less than perfect, either way - you’re looking for a water filter. A simple search on Amazon will return thousands of options that all claim to make your water clean, so what’s next? You’ll be bombarded with claims of 99% reduction in X chemical, claims of certifications to an alphabet soup of scientific standards, and a hefty serving of marketing speak. We’re here to help you navigate through some of these options and help you solve the problem of clean water for you and your family. 

This guide is meant to be a general overview of which types of devices and which features of a given device will work the best for the highest number of people. There will ALWAYS be a perfect solution for a specific contaminant or someone with unlimited funds. This is not who this guide is for. This guide is for those looking to remove the widest range of contaminants from their tap water. 

We will not go into how the dangerous chemicals are getting into the water, as we assume the reader has no control over that. You just want clean water without too much hassle or expense. Let’s get into it. 

Anything Is Better Than Nothing

Even running your tap water through a simple pitcher-style filter like a Britta will remove some contaminants and make your water safer. The most basic filters on the market do work well, but they are not capable of removing the large range of contaminants in modern tap water. All of the filter manufactures will focus on what their device does best, and generally these are factual claims.

If you are not ready to invest the amount of money it will cost to get a full spectrum filtration system including reverse osmosis (more on this later) it is still absolutely worth the smaller investment for basic filtration. 

Reverse Osmosis Is The Gold Standard

Everything other than RO in the drinking water filter market is noise. There is no other widely available technology on the market today that offers a level of filtration even comparable to what is common in every RO system. While it may sound space age, the idea behind RO is pretty simple and there are plenty of resources to learn more about how it works, this video is a great explainer:

If we know that RO will remove the widest range of contaminants, then why doesn’t every filter use this tech? The short answer is that it requires high pressure and pre-filtration to protect the fragile RO membrane, and requires the device to output brine or “waste” water. This introduces a level of complexity to the device that in turn causes prices to increase, and user interface to suffer. 

This guide is not comprehensive in that it includes every option available to consumers, it will focus entirely on reverse osmosis systems. There are many form factors and features available on a wide array of machines. We will get into which features matter most to existing users, and which systems are best for your specific home. 

Types of Residential Reverse Osmosis Systems

There exist two main types of RO for homes, point of use, and point of entry (POU + POE). 

Point of Use - POU systems are installed in the home where the user will be drinking from. They do not purify the water for the whole house, only smaller amounts for drinking and cooking use. These systems are extremely common and usually come in the form of installed under-sink systems or countertop appliances. This guide will be focusing on these POU systems, which generally range from $250-750 plus installation if applicable. 

Point of Entry - POE reverse osmosis systems are much larger and more complex, but they will purify water for the entire house. These are rare to see in homes, but they are starting to be more common in new construction of high-end homes. The system will purify all of the water for the house, including water used for things like toilets and dishwashers. Given that almost all contaminants are the most dangerous to humans when consumed, purifying water for the whole house is generally not a concern for most people. These systems start at around $10k + installation and only go up in price from there.

Installation - The Biggest Barrier to RO

Years ago if you wanted an RO system in your house the only option was to do a full installation, that install includes tapping into your cold water line, tapping into your drain line, and drilling a hole through your sink or countertop for the dedicated RO water spout near the sink. These under-sink installed systems are still the most common, but they are not the only game in town anymore. A new host of countertop devices are on the market that don’t require installation of any kind. Here’s the breakdown of the differences between the types of point-of-use RO systems. 

Under-Sink System Installation

These systems can be installed by anyone who would be comfortable changing out a sink faucet or hooking up a washing machine. They are not overly complex, but individual situations can make install difficult even for professionals for a few reasons:

  1. The number one reason most people don’t want to install under-sink systems is that they rent their home or live in an apartment they aren’t allowed to modify. 
  2. The number two reason people don’t want to install is that they don’t want to drill through their countertop or sink. Replacing the faucet with an integrated Faucet+RO spout can negate this issue.
  3. Non-standard / old plumbing systems - if the threads on your incoming water line aren’t standard/working threads, or your drain line is inaccessible the plumber may have to redo your under-sink plumbing, causing large expense or making install not possible. 
  4. If the water pressure in your home is low (under 40psi) then any under-sink machine you install will require a booster pump, thus also requiring an electrical outlet under the sink. 

Under-sink systems also have a downside to them if the system were to leak. While leaks are rare and generally happen immediately after installation, the device is hooked up to your main water line, so any leak will continue to flow until the water is shut off to the system. 

The bottom line: If you are handy or willing to hire a plumber, under-sink reverse osmosis can work great. There is no tank to refill or anything for the user to do other than turn the faucet to get clean water. Filters must be maintained every 6 months to one year, and nearly all of the machines on the market use an open standard for filters, meaning you do not have to buy them from the same manufacturer who made your RO system. 

No-Install Options (Best for Apartments)

As mentioned above, there are many new devices on the market that require no installation at all. All they need is some counter space and an electrical outlet. If you live in an apartment, it is most likely that you are going to be using a zero-install reverse osmosis system. 

Mechanically, these countertop systems work in the exact same way as the under-sink systems, but they are not connected to any water or drain lines. They use a combination feed+brine water tank that the user manually fills in their sink, and then dumps waste water out when the machine is done filtering the purified wanted into a separate tank. These filters are not able to produce purified water in the same quantity as the larger under-sink systems, purely because of  their size and need for the user to lift water into the machine. 

All countertop systems currently on the market require the user to buy filters from the original manufacturer of the device for the entire life of the device. They operate with a similar model to printers and ink cartridges, though the companies have made replacement filters much cheaper in comparison to ink. Normally it will cost $75-150 per year to replace the filters in a countertop machine. These filters are very easy to replace and can be done by anyone. 

Features / Add-ons of Reverse Osmosis Systems

There are a few features that often get added to RO systems that are extremely helpful for things like killing viruses and bacteria, and adding minerals to the water that get removed during the RO filtration process. The two major features that are relevant to residential RO systems are: 

Ultraviolet Light (UV-C) - UV lights can be added to the machine to sterilize the water after it has gone through the RO process. When the correct wavelength of UV light and correct flow rate is used, these devices will kill 99.9% of living organisms in your water. This includes viruses, bacteria and other microorganisms. It is highly recommended that anyone using an RO system include UV if possible. There is zero downside to doing so. 

Remineralization / Alkaline Water - The reverse osmosis process works so well that it removes nearly all minerals in the water. This will cause a slight drop in pH in the purified water. While people will argue forever over which pH of water is the best for health, the short answer is that if you like alkaline water, you should drink alkaline water. Alkaline water is water with a pH above 7, and adding minerals back to your water post-RO will raise its alkalinity. It is a complete myth that pure RO water strips minerals from your body, but many people like the taste of water with more minerals. Many filter systems will include a module at the end of the process to reintroduce minerals, you can also buy liquid minerals to drop into your water bottle after the fact. 

Our Reviews

If you click the link at the top of this website for Filters, you will see a collection of all of the filters that we have reviewed, including breakdowns of important features, metrics like “Time to Fill 1L Water Bottle”, price charts, and our Best Water Filters rating. 

See Our Reviews

BWF does not do any paid reviews, and if any device was given free or discounted to us by the manufacturer that fact will be disclosed. This website relies on commissions from sales of filters bought via links on this site, so if you found any of this information useful, please consider purchasing via one of our links. It will help keep this project up and running, at no cost to you! 


If you have any questions about the systems on this website, please contact us.