Why Your PUR Filter Is So Slow And How To Fix It

PUR filters may be slow because of air blockages, high sediment levels, hot water or mineral damage, incorrect installation or an old filter. The PUR MineralClear® filter may seem slow as it has a longer filtration time than the basic filter because of greater contaminant reduction.

PUR filters are certified to remove more than 70 contaminants from water – more than most other leading brands. However, sometimes the filtration rate on the PUR faucet filters and filter pitchers may be too slow.

There are 10 specific reasons why your PUR filter is too slow. Below is the complete list of all the reasons why your PUR water filter is slow, and more importantly a step-by-step guide on how to fix each problem.

Types of PUR filters

This article is for anyone who uses a PUR faucet filter or PUR filter pitcher, and whose water filter is not working as it should.

PUR manufactures the following faucet filters and filter pitchers:

  • PUR Basic and Classic faucet filter
  • PUR MineralClear faucet filter
  • PUR Basic filter pitcher
  • PUR Faster filter pitcher

10 Reasons Why Your PUR Filter Is Too Slow

First and foremost the PUR MineralClear® filter removes 99% of lead – far more than the PUR basic filter, resulting in longer filtration times (slower filtration).

If you have recently changed to the MineralClear® filter this may be the cause of your slow filter. However, if that is not the case keep reading to find out why your PUR water filter is so slow.

Water Purification Guide has more information on which PUR filters remove which contaminants available here.

1. Air Bubbles In The Filter

The number 1 reason why PUR filters are slow is because of air bubbles trapped in the filter. This is especially common in the PUR faucet filters!

To remove the air bubbles from a faucet filter or filter pitcher, firstly remove the filter from your faucet filter mount unit or from your pitcher.

Place the filter into a jar or glass of water that is large enough to cover the entire filter with water.

Leave the filter to soak in the water for at least 15 minutes. Remove the filter and gently tap the filter on the side of the sink or bench. Then run tap water over the filter for 20-30 seconds, making sure to hold the filter in an upright position.

Before re-installing the filter into your faucet filter mount or pitcher, it is a good idea to carefully clean the mounting area, to ensure there isn’t any debris that could damage your filtration unit.

2. Filter Housing Blockage

Replacing a water filter can cause debris to become lodged inside the filter housing area.

This type of blockage tends to be more common in filtration devices that require the water filter to be twisted into place.

This is because debris gets caught in the threads of the housing. The PUR faucet filters have either internal or external threading so they are particularly susceptible to this type of blockage.

However, blockages can still happen in any filter type.

To prevent blockages, simply clean the housing area thoroughly every time you replace your water filter, or when installing a new one – And remember to take particular care to wipe along the threads or inside any slots.

3. Old Filter That Needs Replacing

Delaying the replacement of your PUR filter will cause the filtration rate to become increasingly slow. This is because over time the available pore spaces of your water filter become filled with contaminants, making it harder for water to flow through your filter.

Watch the filter change indicator on your PUR device to monitor the filter life and replace the filter as indicated. I find it helpful to always have one filter on hand ready to be installed, so I don’t have to wait.

Here is a quick checklist for how often you should change your PUR filter:

PUR Basic faucet filter100 gallons (or 3 months)
PUR MineralClear faucet filter100 gallons (or 3 months)
PUR Basic filter pitcher40 gallons (or 60 days)
PUR Faster filter pitcher40 gallons (or 60 days)

PUR faucet filters and filter pitchers have a CleanSensor™ Monitor to help you know when to replace your filter.

It is important to reset the PUR CleanSensor™ Monitor every time you change your filter, so that it can accurately record your usage and tell you when it is time for a new filter.

The filter change light will change color depending on how long your filter has been in use or how much water has been filtered.

Also, it is good to remember that the filter change light has a non-replaceable battery. So at some point the battery will eventually stop working, but remember the filter is still functional – You will just need to manually record how long you have had your filter for!!

4. Clogged Filter

If your tap water contains too many sediments – be it clay, minerals, rust or sand – this can cause the filter to become clogged.

A filter that has become clogged with sediment typically has a gradual reduction in the filtration speed. However, on rare occasions a sudden drop in the speed of water flowing from your water filter can also be due to high sediment loads in your water – but this can usually be seen when you turn your tap on.

Unfortunately, water filters become clogged because they are removing the sediment from your water – which is EXACTLY what a filter should do and is completely normal.

Realistically though, you shouldn’t see your water flow slow down until the end of the water filter’s lifespan. However, if your tap water naturally contains a lot of sediment you may need to replace your filters more frequently than what is recommended by PUR.

To check if your tap water contains a lot of sediment, fill a glass of water from the tap and leave it on the counter for 30 minutes. Most sediment will gradually settle to the bottom and is a good indication that your water filter will probably need to be changed more frequently.

Remember – PUR filter pitchers usually take 10-15 minutes to fill the reservoir. If your filter is taking longer than this it can be an indication your filter is clogged with sediment particles.

Water Purification Guide has more information on black water coming from your PUR filter available here.

5. Flushing The Filter Incorrectly (Or Not At All)

All PUR water filters should be flushed before use.

During manufacturing and shipping of your water filter, particles can become dislodged and block the pore spaces of the filter, preventing the water filter from working. This is particularly common for filters made of carbon, such as the PUR water filters.

Filter material coming loose during transport is normal, which is why almost every manufacturer recommends you flush your water filter before use.

Flushing your water filter is simple and easy – just follow these steps:

For a PUR faucet filter – run cold water for 5 minutes, with the device in a filtered position. It is normal to see cloudy water or to hear air being pushed through the filter during this initial flush.

For a PUR filter pitcher – Soak the filter in cold water for 15 minutes and then hold under cold running water for 10 seconds. Fill up the top reservoir with cold water and let it drain. Discard this water and repeat at least once more.

6. Hot Water Damage

It may seem counterintuitive, but water filter pitchers and faucet filters are made to filter COLD WATER ONLY. Running hot water through a filter will damage the filter irreparably and one of two things will happen:

  1. Your filter will be really slow (because of damage to the filter).
  2. Your filter will be really fast (because damage to the filter created large holes and is no longer filtering water).

For PUR faucet filters – Do not use the water above 100˚F (38˚C).

For PUR filter pitchers – Do not use with water above 82°F (28°C).

7. Mineral Damage

Minerals, such as calcium and magnesium, are naturally found in our water supply, and often in high concentrations. These minerals form scale deposits on areas that come into contact with water, building up over time and damaging your filtration device.

Scale is white and typically appears as a hard crusty layer. So it is easy to spot around the home, such as in sinks, on shower heads or faucets.

While many water filters are designed to remove calcium and magnesium from water, PUR faucet filters and filter pitchers are not. Unfortunately, this means the filter attachments are more susceptible to scale damage – particularly the faucet filter.

If you live in area with a water supply that has hard water (or high concentrations of calcium and magnesium) then you may need to resign yourself to more frequent filter changes than you originally expected.

8. Low Water Pressure

Low water pressure can reduce the filtration rate of the PUR faucet filter – the filter pitchers are not affected by this particular problem.

The PUR faucet filter uses tap water pressure to push the water through its filter. To prevent slow filtration ensure the tap is opened sufficiently to provide a steady stream of water.

9. High Water Pressure

High water pressure from your faucet results in aeration of your water – air circulating through your water. This aeration can introduce air bubbles to your filter and slow the filtration rate.

To remove air bubbles soak your water filter in a glass of water for at least 15 minutes and run cold water over it for 20-30 seconds, while holding it in an upright position.

To prevent aeration in the future, ensure your faucet is NOT opened to a full stream. Allow your water to flow smoothly and steadily – you should not observe bubbles.

10. Incorrect Installation

Incorrect installation of a water filter usually occurs when an old filter is replaced with a new one. Typically, the water filter is not clicked, threaded or twisted all the way in. This results in water not passing through the filter or water leaking around the filter.

For PUR faucet filters –

  • Remove the device from your faucet by unscrewing the threaded mounting nut.
  • Twist back cover off
  • Insert the filter into the device (Remember, the filter should fit loosely)
  • Replace back cover
  • Reinstall device on to your faucet

For PUR filter pitchers and dispensers –

  • Simply insert the filter into the pour tray and push down and twist clockwise to lock.


  • Remove all protective caps and packaging before you install the new water filter
  • Gently clean the housing area before installation.
  • Flush the filter before use

Theresa Orr

Theresa Orr is an Earth Scientist who specializes in determining past climates from rocks using geochemistry. Her passion for clean water drives her to breakdown the science to provide easy to understand information that everyone can read.

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