Installing a PUR filter takes five minutes and requires no tools

Most PUR filters screw or slide into place by hand. You turn off the water, unscrew or release the old filter, and hand-tighten the new one until it stops — no wrench needed. The exact steps depend on which PUR model you own: faucet-mount filters work differently from pitcher filters, and under-sink models have their own process. Once installed, you run water through for 5 to 10 seconds to flush the filter before drinking.

The filter itself comes sealed in a plastic wrapper. Do not remove that wrapper until you are ready to install it. Leaving it sealed keeps the filter media dry and prevents contamination during storage.

Key Takeaways

  • Faucet-mount filters unscrew counterclockwise by hand; under-sink filters have a plastic housing you twist to release the old cartridge.
  • Hand-tighten the new filter until snug — do not use a wrench or pliers, which can crack the plastic housing.
  • Run water through the filter for 5 to 10 seconds after installation to flush out loose carbon particles.
  • Keep the old filter's date label or write the installation date on the new filter so you know when to replace it again.

How to replace a faucet-mount PUR filter

Faucet-mount filters sit on top of your kitchen sink tap. Locate the filter housing — the plastic cylinder attached to the faucet. Grip the housing with one hand and turn it counterclockwise with the other until it comes free. You may need to turn it a quarter turn before it releases; some models have a slight resistance at the start.

Once the old housing is off, the filter cartridge inside will either stay in your hand or remain on the faucet. If it stays on the faucet, unscrew it by turning counterclockwise. Discard the old filter. Take the new filter out of its wrapper and screw it onto the faucet by hand, turning clockwise until it is snug. Do not over-tighten.

Screw the housing back onto the faucet by turning clockwise. Again, hand-tighten only — you should be able to remove it by hand next time. Turn on the water and let it run through the filter for 5 to 10 seconds. You may see black specks in the water; this is normal carbon dust from the new filter. After flushing, the water should run clear.

How to replace an under-sink PUR filter

Under-sink filters live in a plastic housing mounted under your sink, usually connected to the cold-water line. Locate the housing and look for the filter cartridge inside — it looks like a white or blue cylinder. Turn the cartridge counterclockwise by hand until it comes free. Some models have a release button you press while turning; check your manual if the cartridge does not budge.

Once the old cartridge is out, take the new one from its wrapper. Insert it into the housing and turn it clockwise by hand until it stops. You should feel a slight resistance as the seal engages. Do not force it. Screw the housing cap back on if you removed it.

Turn on the cold water at the sink and let it run for 5 to 10 seconds to flush the new filter. Check under the sink for leaks where the cartridge meets the housing. A small drip at the connection usually means the cartridge was not turned far enough; turn it another quarter turn clockwise and check again.

How to replace a PUR pitcher filter

PUR pitcher filters sit inside the pitcher itself, held in place by a clip or a threaded post. Open the pitcher and locate the filter — it is the cylindrical cartridge in the center. If it is held by a clip, press the clip to release it and pull the filter straight up and out. If it is threaded, turn it counterclockwise by hand until it comes free.

Take the new filter from its wrapper and insert it into the pitcher, aligning it with the post or clip. If threaded, turn it clockwise by hand until snug. If clipped, push it down until the clip locks into place. Fill the pitcher with water and let it run through the filter into a sink or basin — do not drink this first batch. Empty and refill once more before using the pitcher normally.

Common mistakes to avoid during installation

The most common error is over-tightening the filter. PUR housings are plastic and can crack if you use a wrench or pliers or turn too hard by hand. Hand-tighten only, and stop as soon as you feel resistance. The filter will seal properly without extra force.

Another mistake is installing the filter while the wrapper is still on. The wrapper protects the filter during shipping, but it blocks water flow. Always remove the wrapper before installation. Similarly, do not skip the 5 to 10 second flush after installation — this removes carbon dust that can make water taste bitter or look discolored.

Some people forget to turn off the water before replacing an under-sink filter. You do not have to, but it makes the job cleaner and prevents water from spraying when you remove the old cartridge. If you do turn it off, locate the shutoff valve on the cold-water line under the sink and turn it clockwise until it stops.

When to replace your PUR filter

PUR filters are designed to last 2 to 3 months under normal household use, depending on your water quality and how much water you filter. Write the installation date on the new filter with a permanent marker so you remember when to replace it. Some PUR pitchers have a filter-life indicator light that turns red when replacement is due.

If your water starts to taste odd, smells like chlorine again, or flows more slowly than usual, the filter may be clogged before the 2 to 3 month mark. This happens in areas with very hard water or high sediment. Replace it early if you notice these signs. Do not try to clean or reuse a PUR filter — they are designed for single use only.

Frequently Asked Questions

Do I need to turn off the water before replacing an under-sink filter?

No, but it is easier if you do. Turning off the cold-water shutoff valve under the sink prevents water from dripping when you unscrew the old cartridge. If you do not turn it off, have a towel ready to catch drips. The shutoff valve is usually a small knob on the cold-water line; turn it clockwise until it stops.

Why is my water black or discolored after installing a new filter?

The new filter releases loose carbon particles during the first use. Run water through for 5 to 10 seconds and discard it. Refill and the water should be clear. If it stays discolored after two or three flushes, the filter may be defective — contact PUR for a replacement.

Can I use a wrench to tighten the filter?

No. PUR housings are plastic and crack easily under wrench pressure. Hand-tighten only until you feel resistance, then stop. The filter will seal properly without extra force and will be easier to remove next time.

What if the filter leaks after I install it?

For under-sink models, the cartridge may not be turned far enough. Turn it another quarter turn clockwise and check for leaks. For faucet-mount filters, make sure the housing is screwed on tightly. If leaking continues, the filter or housing may be defective — contact PUR with your model number and purchase date.

How do I know which PUR model I have?

Check the packaging your filter came in or look for a model number on the housing itself. PUR faucet-mount models are labeled FM-3700, FM-4000, or similar. Under-sink models are labeled PUR-US or PUR-PLUS. Pitcher models are labeled PUR-18 or PUR-30. Your model number tells you which replacement filters to order.