Pentair Big Blue Housing 20 Inch With Pressure Relief

So, you’re thinking about water filtration. Congratulations! You’ve just signed up for a deep dive into the most thrilling topic since… well, since watching paint dry, but with way more plastic. But hold on—don’t click away. I’m about to introduce you to the unsung hero of your plumbing system: the Pentair Big Blue Housing 20 Inch With Pressure Relief. This thing is less a filter and more like a water bodyguard with a PhD in hydraulics and a great sense of timing.

First off, let’s talk about the name. Big Blue. It sounds like a burly cartoon character who wrestles bears for fun. And honestly? That’s not far off. This housing is a chunky blue cylinder that could probably double as a small trash can in a pinch (please don’t test this). It filters water for your whole house, not just a sad little pitcher in your fridge. Your fridge pitcher? That’s like using a teaspoon to empty a swimming pool. Big Blue is the fire hose of the filtering world.

Why so serious? Let’s talk pressure

Now, here’s where it gets juicy—and by juicy, I mean potentially explosive. Without a pressure relief valve, your water filter housing can become a ticking time bomb. Literally. Water pressure can build up inside, and if you forget to release it before unscrewing the cap, BOOM. It’s not a dramatic boom with confetti and a smoke machine—it’s a wet, angry boom that drenches your basement and your dignity.

That’s why Pentair added a built-in pressure relief button right on top. It’s a tiny red or black button that looks innocent, but it’s actually a hero in disguise. Press it, and you hear a soft hiss—like a relieved sigh from your plumbing. It’s the water equivalent of cracking a soda can before opening it. If you ignore that button, you’re basically inviting a water geyser to your filter-changing party. And I promise, nobody wants that party.

Size matters, and 20 inches is big

Why the 20-inch version and not the wimpy 10-inch? Because size matters when it comes to holding dirt. A 20-inch filter cartridge has twice the surface area, meaning it catches more sediment, rust, and mystery gunk from your pipes. Your water will come out so clear, you’ll think you’re drinking bottled water from a fancy spa. And the best part? You only change the filter once every six to twelve months. That’s almost as infrequent as me cleaning my office (don’t judge).

Plus, this housing is built like a tank. It’s made from reinforced polypropylene, which sounds like something a robot would wear to a demolition derby. It can handle up to 125 PSI of pressure, which is the equivalent of a jet engine on a bad day. You could probably drop this thing off a two-story building and it’d just bounce. Probably. I haven’t tested that, but I’m not saying it’s impossible.

The shocking fact you didn’t know

Here’s a surprising nugget: that little pressure relief button isn’t just for you. It’s also a safety feature in case your water heater goes rogue. If the water in your system gets too hot, the pressure can spike dangerously. The button gives you a manual way to release that pressure before your housing turns into a torpedo. And yes, a torpedo of hot water is terrifying. You’re welcome for that mental image.

PENTAIR 20" Blue Housing 3/4" MB with pressure release - NO20BL3/4W

But the real shocker? The Pentair Big Blue housing is actually modular. You can stack multiple housings together like giant blue LEGOs to filter for different things—one for sediment, one for carbon, one for fluoride. Suddenly, your basement looks like a water science lab straight out of a mad scientist’s dream. It’s oddly satisfying, like watching a robot build a car while whistling.

Installing it is a comedy of errors—but you’ll survive

Let’s be real: installing any filter system involves about 47 trips to the hardware store, one stripped screw, and a moment where you yell at your pipes in frustration. But the Big Blue housing is shockingly easy to install. It comes with a standard 1-inch NPT inlet/outlet, which is plumber-speak for “it fits most pipes.” You just screw it onto your existing plumbing, tighten it with a wrench—not too tight, you monster—and you’re done. The hardest part is refraining from high-fiving your own reflection afterward.

And when it’s time to change the filter? You press the pressure relief button first (remember the hiss?), then unscrew the clear or blue sump. Some models have a clear bottom so you can watch the gunk accumulate—which is both gross and mesmerizing. It’s like a nature documentary, but for your water. “And here, we see the mighty iron particles settling into the sediment depths…” You’ll start narrating your own plumbing. It’s fine. We all do it.

The bottom line (or should I say, the bottom of the filter)

Look, I know water filtration isn’t the sexiest topic in the world. But the Pentair Big Blue Housing 20 Inch With Pressure Relief is the Sam Elliott of water filters: tough, reliable, and with a voice that whispers “I’ve got you covered.” It doesn’t get clogged easily, it won’t explode if you remember the button, and it will turn your cloudy tap water into something you’d serve to a snooty dinner guest. That guest? They’ll ask, “Is this Evian?” And you’ll smirk, nodding wisely while secretly knowing it came from a big blue plastic tank that could double as a weapon in a zombie apocalypse.

So go on. Buy the Big Blue. Give it a proper name—I call mine Filter McFilterface. Install it, press that pressure relief button with authority, and rest easy knowing your water is clean, your pressure is safe, and your basement is now the coolest room in the house. Just don’t forget to change the filter. Otherwise, your new blue friend will turn into a big blue petri dish of regret. And trust me, regret doesn’t taste good with morning coffee.