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Triple Stage Big Blue Whole House System — 10″ × 4.5″, 1″ NPT
WHS-3SGC-10BB-E
This page covers specifications, installation, routine filter changes, and the exact replacement parts that fit this model.
Is this your system?
Check these against the unit on your wall. All five should match.
- ✓Three filter housings on a metal mounting bracket
- ✓Housings are large-diameter “Big Blue” — roughly 4.5″ across, blue with black caps
- ✓1″ NPT ports with brass inserts
- ✓A small pressure-release button on top of each cap
- ✓Cartridges are 10″ × 4.5″ (not the slim 2.5″ size)
Big Blue or slim? Check before ordering
MyWaterClub makes whole-house systems in two cartridge sizes, and they are not interchangeable. The quickest test: measure the width of one housing.
- Big Blue (this system) — housings about 4.5″ wide, 1″ ports. Cartridges are 10″ × 4.5″.
- Slim — housings about 2.5″ wide, 3/4″ ports. Cartridges are 10″ × 2.5″. Find your slim model →
Specifications
| Model / SKU | WHS-3SGC-10BB-E |
| Stages | 3 — Sediment (5 µm) → GAC (25 µm) → CTO carbon block (10 µm) |
| Housing size | 10″ × 4.5″ (Big Blue) |
| Port size | 1″ NPT with brass inserts · pressure-release buttons |
| Housing color | Blue with black caps |
| Operating temperature | Max 100°F · do not allow to freeze |
| Typical filter life | ~6–12 months per set (varies with water quality & volume) |
| Shipped with | 2 complete filter sets (1 installed + 1 spare), mounting bracket, housing wrench |
| Brand | MyWaterClub |
Manual & installation
Installation manual (PDF)
Mounting, 1″ NPT connections, startup, and the filter-change procedure.
Install on the main cold-water line after the meter or pressure regulator. This system connects to 1″ NPT plumbing — a qualified plumber is recommended if you’re not comfortable working on house lines.
Fit shutoff valves on both sides
This system doesn’t include built-in shutoffs. A ball valve on the inlet and the outlet lets you isolate the unit for filter changes without shutting off water to the whole house. If your installer didn’t fit them, you’ll need to close your main house shutoff before every filter change.
Mount into solid framing
Big Blue housings hold a lot of water. Filled and in service, this system is considerably heavier than it feels empty — fasten the bracket into studs or masonry, not drywall alone. Protect it from freezing and keep it out of direct sun.
When to change your filters
| Component | Typical interval | Change sooner if… |
|---|---|---|
| All 3 cartridges Change as a complete set |
~6–12 months | Water pressure drops · taste or odor returns · visible discoloration · heavy sediment or well water |
| Housing O-rings | Inspect every change Replace every 12–24 months |
Cracked, flattened, brittle, or weeping at the seam |
| Filter housings | 3–4 years | Any crazing, hairline cracks, cloudiness, or a leak that a new O-ring doesn’t stop |
Intervals are typical estimates. Your water chemistry, pressure, and household usage determine the real schedule. Big Blue cartridges hold more media than slim ones, which is why they generally run longer between changes.
Important: replace the housings every 3–4 years
Filter housings are under constant line pressure. Over years the plastic fatigues and can crack without warning — and a failed Big Blue housing on a 1″ main line releases water fast enough to flood a home.
Replace all housings on this system every 3–4 years regardless of appearance, and immediately at any sign of crazing, cracking, or a persistent leak. Write your install date on each housing with a marker, or on the magnet, so the next change is easy to date.
Which replacement set fits this system
Both sets below fit the same Big Blue housings — the difference is the carbon media.
Matches your system · SGC-10BB
Standard Set — Sediment + GAC + CTO Carbon Block
The like-for-like replacement for this model. One complete change for all three stages: SED5-10BB, GAC-10BB, CTO-10BB.
Premium upgrade · SCGACCACB-10BB
Premium Set — Sediment + Coconut GAC + Coconut Carbon Block
Same fit, same three stages, with coconut-shell carbon in both carbon positions — denser media, longer carbon life, finer taste and odor polishing.
Replacing a single stage
Cartridges are also sold individually if you only need one stage, or want to swap a stage for a different media.
SED5-10BB — Sediment → ·
GAC-10BB — GAC carbon → ·
CTO-10BB — Carbon block →
Water problem the standard set doesn’t cover?
Any of the three stages can take a different Big Blue media cartridge. Common swaps: catalytic carbon for chloraminated city water, bone char for fluoride, iron or scale-inhibitor media for well-water problems.
Browse all Big Blue cartridges → · Ask us what fits your water →
Specialty cartridges for this system
Any stage in this system can take a different Big Blue media cartridge. If your water has a problem the standard sediment-and-carbon set doesn’t address, swap the matching stage rather than buying a second system.
Keep sediment first
Whatever you swap, Stage 1 stays a sediment cartridge. It protects every stage behind it. Specialty media go in Stage 2 or Stage 3, in place of the GAC or the carbon block.
| Cartridge | Best for | What it does |
|---|---|---|
| Stage 1 — Sediment | ||
| Pleated Sediment — Washable
SED5-PLT-10BB · 5 µm
|
Heavy sediment & well water | A pleated cartridge that traps dirt, silt, sand, and rust particles like the standard sediment filter, but can be rinsed and reused instead of replaced. Worth the swap if your Stage 1 is loading up fast enough that you’re changing it more often than the carbon stages. |
| Carbon stages — use in place of GAC or the carbon block | ||
| Advanced Catalytic Carbon
CAT-10BB · 25 µm · Centaur®
|
Chloraminated city water | Catalytic carbon made with Centaur® by Calgon. Standard GAC and carbon block have limited effect on chloramine — this media is the correct swap if your utility disinfects with chloramine rather than free chlorine. Also helps reduce hydrogen sulfide (rotten-egg smell). |
| Premium Catalytic + KDF-85
CATKDF85-10BB · 25 µm
|
Chloramine + H₂S + metals · longest life | Catalytic carbon blended with KDF-85 media. Covers everything the catalytic cartridge does and adds heavy-metal reduction. The KDF component also inhibits bacterial growth within the media bed, which is why this cartridge typically runs the longest of the carbon options. The most capable carbon stage in the range. |
| Specialty media — targeted water problems | ||
| Bone Char
BC-10BB · 25 µm
|
Fluoride, heavy metals & arsenic | Bone char is one of the few media that helps reduce fluoride under suitable conditions, alongside heavy metals and arsenic. It also handles chlorine, taste, and odor, so it can stand in for a carbon stage rather than needing one of its own. Performance depends on contact time and water chemistry. |
| Iron Reduction + Softening Resin
IRON-10BB
|
Clear-water iron & light softening | Softening resin that reduces dissolved iron, manganese, and some hardness — the usual fix for orange staining in sinks and laundry on well water. For clear-water (dissolved) iron only. If your water comes out of the tap already orange or rusty, the iron has oxidized and needs a backwashing iron system instead. This is a supporting stage, not a whole-house iron filter. |
| Scale Inhibitor — Salt-Free
SCALE-10BB
|
Limescale protection | Conditions hardness minerals so they’re less able to form scale in pipes, water heaters, and appliances. No salt, no drain, no backwashing. Important: this does not remove hardness minerals and is not a water softener. Your water will still test hard and still feel hard — the benefit is scale protection for your plumbing, not soft water. |
All cartridges above are Big Blue 10″ × 4.5″ and drop straight into this system’s housings. Filter life varies by media and by your water — see each product page for its interval.
Not sure which one you need?
The right swap depends on what’s actually in your water, and more than one of these can be wrong for a given problem. A water test is the reliable way to choose — guessing usually costs more than testing.
Browse all Big Blue specialty cartridges → ·
Send us your water report → ·
Free basic testing in San Diego →
Parts that fit this system
Also available on Amazon. Big Blue parts are a different size from slim 10″×2.5″ parts — make sure you’re ordering the Big Blue version.
Changing your filters
- Shut off the water. If shutoff valves were fitted either side of the system, close both. If not, close your main house shutoff.
- Open a cold tap downstream, then press the pressure-release button on top of each housing until it stops hissing. Never open a housing under pressure.
- Put a bucket and towels underneath. Each Big Blue housing holds well over a gallon — considerably more than a slim housing, so plan for the spill.
- Unscrew each housing with the Big Blue wrench, supporting its weight as it comes free.
- Remove the old cartridge. Rinse the housing with clean water; no soap or detergent.
- Inspect the O-ring. If it’s flat, cracked, or brittle, replace it. Seat it fully in its groove and wipe it with a thin film of food-grade silicone grease.
- Fit the new cartridge, keeping stage order: Sediment → GAC → CTO Carbon Block, following the direction of water flow.
- Hand-tighten each housing, then snug it with the wrench. Do not overtighten — overtightening cracks housings and distorts O-rings.
- Turn the water back on slowly. Check every seam and both 1″ connections for leaks.
- Run a nearby cold tap for 10–15 minutes to flush carbon fines. Grey or cloudy water at first is normal and clears.
- Write the date on the housing or your magnet so the next change is easy to schedule.
Common questions
| What you’re seeing | Most likely cause |
|---|---|
| Water pressure has dropped through the house | A loaded sediment cartridge, usually Stage 1. This is the normal end-of-life signal — change the set. |
| Leak where the housing meets the cap | O-ring not seated in its groove, or worn. Depressurize, reseat or replace the O-ring, lightly grease it. |
| Water weeping from the pressure-release button | Debris under the button seal, or a worn button. Depressurize and press it several times to clear it. If it keeps weeping, replace the housing. |
| Housing won’t unscrew | Pressure still in the housing, or it was overtightened last time. Confirm the water is off and you’ve pressed the release button, then use the Big Blue wrench. |
| Grey or cloudy water after a filter change | Carbon fines and trapped air. Normal. Flush a cold tap for 10–15 minutes. |
| Chlorine taste or smell has come back | Carbon stages are exhausted. Change the set. If your utility uses chloramine rather than chlorine, standard carbon has limited effect — a catalytic carbon cartridge is the right swap. |
| Water is still hard, or leaves scale | Expected. This is a filtration system, not a softener — it does not remove hardness minerals. |
| The cartridges I bought don’t fit | Almost always slim 10″×2.5″ cartridges bought by mistake. This system takes the wider 10″×4.5″ Big Blue size. |
Need help identifying a part?
Scope note: This is a sediment-and-carbon filtration system for improving everyday water — it is not a certified microbiological purifier and does not soften water or remove dissolved minerals. Do not use it to make microbiologically unsafe water safe to drink; on an untested well or under a boil-water advisory, treat your water accordingly first.
Please note: Filter life and reduction performance depend on your water chemistry, pressure, and usage, so results vary from home to home. This product is not certified to treat water of unknown quality and is not a substitute for testing your water. Descriptions use general, qualified language and are not health claims. When in doubt, test your water or ask us and we’ll help you build the right stack.