How to Change a Well Water Filter (10 Steps with Pictures)

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Well water filters might seem like a quick fix to your contaminated water issues – but they need long-term maintenance in order for them to be a long-term solution.

One of the essential maintenance tasks is replacing your filters. In this guide, we’ve outlined exactly how to replace your well water filters, step by step.

📌 Key Takeaways:

  • To change a well water filter:
    • Switch off your water supply and depressurize the system
    • Remove the filter housing and discard the old filter
    • Clean the filter housing, clean or replace the o-rings, and add the new filter to the housing.
  • Replacing a well water filter is essential to prevent reduced flow rate, recontamination of your water, and bacteria buildup in the filter media.
  • You should aim to replace a well water filter every 6-12 months, depending on the filter type and size.

📖 How to Replace a Well Water Filter: Step-By-Step

Follow the quick steps below to replace the cartridges in your whole house filter unit.

Step 1: Gather Your Tools

Before you start, make sure you have the right tools to replace your filters.

You will need:

  • A new filter
  • (Optional) a new o-ring
  • A filter wrench or tea towel
  • A bucket
Step 1 - Gather Your Tools

Step 2: Shut Off Your Water

Whole house water filters intercept your main water line, so you’ll need to shut off your POE water supply to safely replace your filters.

Find the valve upstream of your water filter (sometimes it’s outside your home or in your basement), then turn the valve to completely shut off the water.

Open several faucets to drain water out of the pipes and relieve the pressure.

Step 2 - Shut Off Your Water

Step 3: Relieve The Filter Pressure

Most whole house filters have a pressure release button – usually red in color – on top of the filter unit. Press this button to relieve pressure inside the unit. This will make it easier to remove and replace the filters.

Step 3 - Relieve The Filter Pressure

Step 4: Use A Wrench To Remove The Filter Housing

Identify which filter needs to be replaced, then use your filter wrench to unscrew the filter housing (also known as the filter head or canister).

If you don’t have a filter wrench or you can’t find it, use a kitchen towel to get a good grip on the housing. You might need to put some force in if you haven’t opened the housing in a while.

Place an empty bucket directly beneath the housing to catch any remaining water inside the unit.

📌 Note: to avoid damage to the housing, don’t use a metal wrench unless you’ve exhausted all other options.

Step 4 - Use A Wrench To Remove The Filter Housing

Step 5: Remove The Old Filter

Once you’ve unscrewed the housing, tip it upside down to remove the existing filter. Put the filter to the side for now. Check your user manual for instructions on how to safely discard the old cartridge.

Step 5 - Remove The Old Filter

Step 6: Clean the Filter Canister

You might notice that the housing looks dirty or feels slimy. We recommend cleaning the housing every time you replace a filter.

Soak the housing in warm, soapy water, then use a sponge to scrub the inside of the canister. Dry the canister thoroughly before moving on to the next step.

Step 6 - Clean the Filter Housing

Step 7: Clean & Lubricate or Replace O-Ring

Check the o-ring that sits between the filter and the housing. The o-ring may be dirty, cracked, or worn after so many months of use.

Decide whether or not the o-ring is suitable for cleaning, lubricating, and reuse. If it is, clean the o-ring carefully under warm, running water, then grease the ring with food-grade silicon grease. If not, discard the o-ring and fit a replacement o-ring in its place.

Replacing an old o-ring is essential to prevent leaks inside the system.

Step 7 - Clean & Lubricate or Replace O-Ring

Step 8: Install The New Filter

Slot the correct replacement filter in the housing. Make sure it’s pushed all the way in and the o-ring has formed a tight seal in the canister.

Step 8 - Install The New Filter

Step 9: Reattach The Housing

Finally, screw the housing back in place, using the filter wrench to tighten it.

Step 9 - Reattach The Filter Housing

Step 10: Switch On Water & Check For Leaks

Slowly open your water supply and switch on a nearby faucet. Check the unit for leaks. If you notice leaking, turn off the water and check that the housing is tight enough and the o-rings are forming a proper seal.

Step 10 - Turn Water Back On & Check For Leaks

▶️ Video Instructions

🤔 Why Is Replacing a Well Water Filter So Important?

Replacing the filters in your whole house water filter isn’t an option – it’s essential.

If you don’t replace a well water filter, you’re at risk of:

  • Bacteria buildup in the filter, due to the unsanitary environment created by the dirty filter
  • Reduced filter contaminant removal, caused by decreased performance due to clogging
  • Recontamination of drinking water, as a result of holes forming in the old filter
  • Reduced flow rate, due to the clogged filter limiting how much, and how quickly, water passes through

In short, failing to reduce your water filter won’t only rob you of the benefits of filtered water – it might actually make your water dirtier than it was in the first place.

📆 How Often Should You Replace a Whole House Well Water Filter?

The average whole house water filter for well water lasts 6-12 months. However, some filters last for as little as 2 months before a filter replacement is needed.

Most whole house water filter systems use multiple filter cartridges, each with their own lifespans. Sediment filters usually come first, so they tend to get clogged faster than later filter stages (such as KDF and carbon filters).

Check your user manual to find out exactly how often a new filter is needed.

Factors affecting the frequency of filter changes are:

  • The filter size and surface area – The bigger the filter, the larger its capacity, and the more room for trapped contaminants on the surface area.
  • The filter media type – Certain types of filter media are longer-lasting than others.
  • The filter pore size – The smaller the filter’s pores, the greater the range of contaminants it’ll trap, and the faster it’ll become clogged.
  • Your water usage – If you use more water than average, the filter will become clogged at a faster rate than if you use less water than average.
  • Your water quality – If your water’s TDS count is higher than average, the filter will be exposed to a greater range of contaminants in a shorter space of time, causing it to clog faster.
How to change well water filter cartridges

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🔎 How to Tell When a Well Water Filter Needs Changing

Some of the signs that your whole house well water filter needs changing are:

Poor-Tasting Water

Poor-tasting water is the first sign that you need to buy a replacement filter for your whole house water filter system.

Most well water filters can remove contaminants that contribute to poor taste, including iron and other heavy metals. If your tap water starts to taste or smell unpleasant, it’s probably because these contaminants are back in your water supply.

An old, smelly water filter cartridge could also be contributing to the poor taste and smell of your water.

Slow Water Flow

The second sign that you need to replace your whole house water filter is reduced water flow or water pressure.

It’s normal for a filtration system to slightly reduce your flow rate, but if you only get a slow flow of water even when you turn your faucet on full, it’s an indication that your filter needs changing.

Old filters reduce flow rate because their surfaces are too clogged with contaminants to allow water to flow through.

Low water flow

Dirty-Looking Water

Cloudy or dirty water is the final sign to look for if you’re unsure whether or not to replace a filter.

A depleted filter may allow contaminants to pass through the media, so you won’t have the same clean, clear water as you did when the filter was working properly.

Don’t rely on these signs, though.

If your filter reaches the end of its lifespan and your water still tastes and looks okay, that doesn’t mean you shouldn’t replace the cartridge. Many contaminants in water – including bacteria – are tasteless and odorless – so you won’t necessarily know if they’re being properly removed by a water filter system or not.

🧰 Well Water Filter Change Troubleshooting

Struggling to remove your well water filter housing or cartridge? Here’s what to do.

Stuck Filter Housing

Your filter housing might be stuck because of a buildup of pressure in the system, cold temperatures causing the plastic to shrink, or hard mineral deposits inside the housing, or overtightening the housing.

📌 To fix a stuck filter housing, depressurize the unit, then use a filter wrench or a dishtowel to unscrew the filter. If that doesn’t work, try (carefully) with a metal filter wrench or a rubber strap wrench. Tap the housing to dislodge it, or use a hair dryer to heat the plastic, causing it to expand.

Removing a stuck filter cartridge from canister

Stuck Filter Cartridge

Your filter cartridge might get stuck in the housing due to hard deposits or debris buildup inside the housing, increased pressure in the system, or a clogged, expanded filter.

📌 To remove a stuck filter cartridge, use needle nose pliers to pull the filter out. If that doesn’t work, apply heat to the housing to warm it up, then tap the housing on the floor to loosen the filter before trying again with the needle nose pliers.

Stuck filter housings and cartridges are pretty common – so much so that we’ve published a full guide on how to resolve a stuck filter to help people dealing with the problem.

❔ How to Replace a Well Water Filter: FAQ

How often should a well water filter be changed?

A well water filter should be changed every 6-12 months on average, depending on your water usage and quality, the filter type, micron size, and materials, and the filter size and surface area.

Where is the well water filter located?

Most well water filters are located at your home’s point of entry, downstream of the pressure tank, upstream of your water heater. Many well pumps have a filter, too, which is located on the pump itself.

How do you know when to change your well filter?

You’ll know when to change your well filter because your water pressure will drop noticeably, your water supply might take on a dirty appearance or unpleasant taste, or your water looks cloudy. Ideally, make a note in your diary X months on from the filter installation (depending on the expected filter lifespan) to make sure you don’t forget to replace the filter.

How long does a well water filtration system last?

A well water filtration system lasts for years – often longer than a decade – with proper care and attention. Make sure to replace the filters as recommended by the manufacturer and clean/sanitize the unit at least once a year.

  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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