Pentair Big Blue 3/4 Inch NPT Filter Replacement: Your Questions Answered, Simple and Fast Guide

Okay, so here’s my experience with replacing a Pentair Big Blue 3/4 inch NPT filter.

I noticed the water pressure in my house was getting a little weak, and the water started tasting a bit off. I figured it was probably time to change the whole house water filter. I’ve got one of those Pentair Big Blue ones, and it’s been a while since I last swapped it out.

First, I went and turned off the main water supply to the house. Don’t want any surprises, you know? Then I found the pressure release button on top of the filter housing. I pressed it down to release any built-up pressure, made it a lot easier to work with.

Next, I grabbed the wrench that came with the housing, It’s a big plastic thing. I used it to unscrew the housing from the cap. It was a little tight, but it eventually came loose. Once it was off, I could see the old, gunky filter inside.

I carefully pulled out the old filter. Man, it was dirty! I made sure to have a bucket handy to catch any dripping water. Then I took out the old O-ring from the housing. It’s important to replace that too, to ensure a good seal.

I had already bought a new filter and O-ring. The filter itself was a Pentek NCP-20BB, a carbon sediment one, supposed to be good for taste and odor. I popped the new O-ring into the groove on the housing, making sure it was seated properly.

• Slid the new filter into the housing.
• Carefully screwed the housing back onto the cap.
• Used the wrench to tighten it up. I made sure not to overtighten, just snug enough to prevent leaks.

Once everything was back together, I slowly turned on the main water supply again. I checked for any leaks around the housing, and it all looked good! I ran the water for a few minutes to flush out any air or loose carbon from the new filter.

The water pressure is definitely back to normal, and the water tastes much better now. It wasn’t too difficult of a job, took me maybe 30 minutes total. I heard that you should replace the housing about every 10 years, I have had mine for about 8 years, so I will be looking to replace it soon. I should probably do this more often, though. It’s pretty satisfying to have clean, fresh water again!