Filtration Technology

How Often Should I Change My Water Filters?

4 min read

Even if your water still tastes and smells fine, your filters could be failing you.

This is what happens when you don’t replace them periodically.

Don’t be a failure!

Most water systems include several different types of filters.

Here’s how often you should replace each of them:

Sediment pre-filter: Every 6-12 months Carbon pre-filter: Every 6-12 months Reverse osmosis membrane: Every 24 months Polishing filter: Every 12 months

Let’s take a closer look...


The most obvious signs that it's time to change your water filter are slow flow rate, bad tastes and nasty smells.

Factors that affect filter lifespan are frequency of use, water contamination levels, filter cartridge type, and filtration system design.

If you don't change your filters regularly, they can become clogged with unwanted gunk and saturated with toxins.

Treating water with an old filter can be worse than not filtering it at all. Toxins that are stuck in the filter membrane can break off and further contaminate your drinking water.

How to Tell If Your Water Filter Needs Changing

Unpleasant odor, bad taste, discoloration and decreased flow rate are the obvious signs that your water filter might need to be changed.

If you have a reverse osmosis (RO) system and you don’t notice any of these signs, you can use a TDS meter to check if your RO membrane is still working. 

Another option is to test your water for contaminants with a do-it-yourself testing kit or an EPA-certified water testing lab in your area.

Factors That Affect Filter Lifespan

How long a filter lasts depends on:

  1. How often you use it
  2. Contamination levels
  3. Type of filter
  4. Type of filtration system

Let’s check these out in a little more detail...

1. Water Usage

The more you use your filter, the faster the toxins will build up and the sooner it will need to be replaced. 

A family of four may need to replace the carbon filter on their new under-sink system every 6 months. However, a couple with no kids may only need to replace it once a year.

time to check YOUR contamination levelS

The type and amount of contaminants play a major role in the lifespan of your water filter. The more contaminants there are, the faster your filter ages. Enter your zip code below to check the water quality in your area.

2. Contamination Levels

More contaminants means more wear and tear. 

A carbon pre-filter will wear out faster if the chlorine levels in your city are high, and you may have to replace it every 6 months instead of 12. 

3. Type of Filter

Sediment and carbon filters have shorter lifespans than RO membranes and polishing filters because they take the brunt of the abuse.

By the time the water reaches the RO membrane and polishing filter, the water is already a lot cleaner. 

4. Type of Filtration System

Not all water filtration systems are created equal. 

Some, like RO systems, are designed to handle heavily contaminated water without having to change filters too often. 

Simple carbon filters, on the other hand, are less effective and need to be changed more often. 

5 Common Water Systems and When Their Filters Need to Be Replaced

There are water filtration systems for every occasion. Some fit under your sink, some attach to your faucet, some sit on your counter, and others connect to your fridge.

But they all have one thing in common: at some point, their filters are going to need to be replaced. 


Reverse osmosis filters were first designed to desalinate seawater and produce drinkable water in remote areas. Today, it's one of the most popular and effective ways to filter water at home.

1. Reverse Osmosis Filters

Reverse osmosis (RO) filters work by forcing pressurized water through a semipermeable membrane with ultra-fine pores. Contaminants get trapped on one side, and filtered water flows right on through. 

RO systems remove 99.9% of dangerous contaminants. 

Most RO systems last between 10 to 15 years, but the RO-membrane, pre-filters and post-filters need to be replaced every 6 to 24 months. 

  • Sediment and carbon pre-filters: Every 6 months to a year
  • Polishing and post-filters: Once a year
  • RO membrane: Every 2 years

Some RO membranes can last longer if they include a water softener and the pre-filters are changed regularly.

2. Water Pitcher Filters

Water pitcher filters are hand-held containers with a sediment and carbon filter inside. They use gravity to slowly filter roughly 3 liters of water at a time. 

The carbon and sediment filters need to be replaced at least every six months, but if you fill it several times a day you may have to replace them more often.

Pitcher filters improve the smell and taste of the water by removing chlorine, as well as trace heavy metals and other contaminants.

3. Faucet Filters

Faucet filters attach directly to the spout of the kitchen faucet. 

Similar to water pitcher filters, they use activated carbon to remove chlorine and other basic contaminants.

Although they’re easy to install, they have a couple downsides: you’ll have to replace them more frequently than other types of filters and they can reduce the flow rate pretty significantly. 

A large family might have to replace their faucet filter as often as once every 3 months, but smaller households should last around six.

4. Countertop Filters

A countertop water filter is essentially a jumbo-sized pitcher filter that sits on the kitchen counter. 

The larger size means that they can squeeze in extra features, like mineral balls to help balance the water’s pH.

But countertop filters cannot remove high concentrations of dangerous contaminants. For that, you’ll want to stick with an RO system. 

Countertop filters need to be changed every 6 to 12 months depending on how often it gets used.

5. Whole House Filters

Point-of-entry reverse osmosis (RO) systems can protect the entire house from “hard” water and 99.9% of dangerous contaminants. 

Because they process such a high volume of water, the filters may need to be replaced every 3 to 6 months. 

In most cases, a whole house system is a little overkill unless you have extremely “hard” water that gunks up your pipes, or if you want to protect yourself from bacteria and chemicals that irritate the skin and might make you sick. 

Replacing your water filter on time doesn't just protect your family from dangerous contaminants, it also improves the taste of your water by removing foul-smelling particles. Delish!

Replacing water filter improves water quality

What Happens If You Don’t Replace Your Water Filters?

If you neglect your filters, they can clog with debris, grow bacteria, and become saturated with toxins.

Old carbon filters are notorious for trapping contaminants and then leeching them back into the system. Instead of taking toxins out, they add them back in! 

Luckily, there’s a way to guarantee that your filters are always replaced at the right time...

Cloud Water Filters use built-in software to track your water usage and automatically ship replacement filters and RO membranes directly to your door. 

Click here to learn more.


Do you know what’s in your tap water?

Have you thought about what's in your tap water? You should check.