Upper seal
AS568-252 Upper O-Ring
The smaller upper O-ring sits in the upper sealing groove. Its dimensions are 5.234″ ID × 5.512″ OD × 0.139″ cord.
Big Blue O-Ring Set — Upper + Lower Gaskets for 10″ & 20″ × 4.5″ Double O-Ring Housings, SKU: GASKETBB-2
$5.99
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Description
Big Blue housing replacement seals
Upper + lower O-ring set for 10″ and 20″ Big Blue filter housings
This matched O-ring set includes the upper and lower seals used in compatible MyAquaFilter Big Blue housings with two O-ring grooves. Both seals are supplied together because the housing requires both sizes for proper sealing.
2 O-ringsUpper + lower matched pair
10″ + 20″Compatible Big Blue housings
0.139″ cordCorrect seal thickness
BunaFood-grade rubber
What it does
Restores the seal between the Big Blue housing sump and cap
Compatible double O-ring Big Blue housings seal against the cap using two separate O-rings — a smaller upper seal on the inner lip and a larger lower seal below it. Both seals remain compressed whenever the housing is assembled and pressurized.
Lower seal
AS568-254 Lower O-Ring
The larger lower O-ring sits in the lower groove. Its dimensions are 5.484″ ID × 5.762″ OD × 0.139″ cord.
Key benefits
Matched replacement seals for compatible double O-ring housings
Matched Upper + Lower Pair
Both required housing seals are supplied together, reducing the chance of replacing only one worn O-ring or ordering mismatched sizes.
Fits 10″ and 20″ Housings
Compatible MyWaterClub 10″ × 4.5″ and 20″ × 4.5″ housings using the same double O-ring cap design use the same matched pair.
Correct Cord Thickness
Both seals use a 0.139″ cord thickness. Cord thickness is critical to achieving proper compression inside the housing grooves.
Food-Grade Buna
Food-grade Buna rubber suitable for compatible cold potable-water filtration applications.
Helps Stop Housing Leaks
Replacing flattened, hardened, twisted, or damaged O-rings can restore the sealing surface between the sump and housing cap.
Multi-Stage Compatible
Use one complete O-ring set per housing in compatible single-, dual-, or triple-stage Big Blue filtration systems.
Compatibility
For compatible MyWaterClub double O-ring Big Blue housings
These seals are intended for housings that use two separate O-ring grooves in the cap. Big Blue-style housings are not manufactured to one universal O-ring specification, so seal dimensions and cord thickness should always be confirmed before installation in another brand.
10BB
10″ × 4.5″ Big Blue
Fits compatible MyWaterClub 10-inch Big Blue housings using the double O-ring cap configuration.
20BB
20″ × 4.5″ Big Blue
Fits compatible MyWaterClub 20-inch Big Blue housings using the same double O-ring cap configuration.
2X
Double O-Ring Housing
Designed for housing caps with two separate seal grooves — one for the smaller upper O-ring and one for the larger lower O-ring.
NO
Not a Universal Big Blue Seal
Other manufacturers may use a single O-ring or different diameter and cord thickness even when the housing appears similar.
Specifications
Confirmed product details
| Product type | Big Blue filter-housing O-ring set |
|---|---|
| Quantity included | 2 O-rings — one upper and one lower |
| Upper O-ring | AS568-252 — 5.234″ ID × 5.512″ OD × 0.139″ cord |
| Lower O-ring | AS568-254 — 5.484″ ID × 5.762″ OD × 0.139″ cord |
| Material | Food Grade Buna |
| Housing compatibility | Compatible My Water Club 10″ × 4.5″ and 20″ × 4.5″ double O-ring Big Blue housings |
| Housing design | Double O-ring cap with separate upper and lower seal grooves |
| Typical service life | Approximately 12–24 months depending on water conditions and service frequency |
| Application | Cold potable water |
| SKU | GASKETBB-2 |
| Alternative SKU | GASKET-10BB |
| Listed shipping dimensions | 5 × 5 × 0.2 in |
| Listed shipping weight | Approximately 0.1 lb |
Correct installation
- ✓Shut off the incoming water before opening the housing
- ✓Press the pressure-release button or otherwise relieve all trapped pressure
- ✓Remove both old O-rings and clean both sealing grooves
- ✓Install the smaller AS568-252 O-ring in the upper groove
- ✓Install the larger AS568-254 O-ring in the lower groove
- ✓Apply only a light coating of food-grade silicone grease
- ✓Make sure each O-ring sits evenly in its groove without twisting
- ✓Repressurize the system slowly and inspect the housing seam for leaks
Replacement procedure
Replace both O-rings while the housing is fully depressurized
1
Shut Off the Water
Close the system inlet and outlet valves or shut off the main water supply before opening the housing.
2
Relieve Pressure
Press the housing pressure-release button and open a downstream faucet until trapped pressure is released.
3
Remove & Clean
Unscrew the sump, remove both old O-rings, and wipe both grooves clean. Dirt or grit underneath an O-ring can prevent a proper seal.
4
Install New Seals
Lightly lubricate both O-rings with food-grade silicone grease. Install the smaller ring in the upper groove and the larger ring in the lower groove without twisting.
5
Reassemble the Housing
Thread the sump onto the housing head by hand. Use only limited final wrench pressure if needed. The O-rings create the seal — excessive torque is not required.
6
Check for Leaks
Turn the water back on slowly and inspect the entire housing seam for at least one minute before leaving the system unattended.
Often used with
Related Big Blue service parts
WR
Big Blue Housing Wrench
Provides additional grip and leverage when opening compatible 10″ and 20″ Big Blue housing sumps.
HSG
10″ Big Blue Housing
Compatible 10″ × 4.5″ housing with 1″ brass-reinforced ports and pressure release.
BR1
Single Big Blue Bracket
Supports one compatible Big Blue housing.
BR2
Dual Big Blue Bracket
Supports two compatible Big Blue housings.
Before installation
Good to know
!
One set is required per housing
Each set contains one upper and one lower O-ring for one housing. A dual-stage system requires two sets and a triple-stage system requires three sets.
!
Big Blue does not mean universal O-ring size
Other manufacturers may use different seal diameters, different cord thicknesses, or only one O-ring even when the housing looks similar.
!
Use food-grade silicone grease only
Apply only a thin coating to the O-rings. Do not use petroleum jelly or petroleum-based lubricant on Buna seals.
!
Do not overtighten the housing
The O-rings create the seal. Excessive tightening can flatten or damage the seals and place unnecessary stress on the housing.
!
Inspect the sealing grooves
Dirt, scale, scratches, damaged grooves, or a distorted housing cap can cause leakage even when new O-rings are installed.
!
Cold potable water only
These seals are intended for compatible cold-water filtration housings and are not intended for hot-water plumbing.
This product includes one matched pair of replacement O-rings only — one AS568-252 upper seal and one AS568-254 lower seal. Filter housing, cartridge, wrench, silicone lubricant, bracket, and plumbing components are not included. Fitment is confirmed for compatible MyAquaFilter double O-ring Big Blue housings listed above. O-ring dimensions and cord thickness vary between manufacturers, so compatibility with other brands is not guaranteed.
Not sure whether GASKETBB-2 fits your housing?
Send the housing brand and model plus a clear photo of the housing cap and O-ring grooves before ordering.
Additional information
| Weight | 4 oz |
|---|---|
| Dimensions | 8 × 6 × 1 in |
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