iSpring WGB21B 2-Stage Whole House Water Filter

Name: iSpring WGB21B 2-Stage Whole House Water Filter
Brand: iSpring
Price: 173.99 USD

Whole-house filter · 15 GPM · Treats sediment · $174 (sale) at iSpring as of Oct 2026

The iSpring WGB21B is a compact two-stage cartridge system using 10 in. by 4.5 in. housings: a 5-micron polypropylene sediment cartridge followed by a 5-micron coconut-shell CTO carbon block. It covers sediment and rust plus chlorine (up to 99%, a maker claim), taste and odor, VOCs, pesticides and herbicides. The page says it does not reduce TDS, bacteria, fluoride, arsenic or chloramines, and it does not treat iron, manganese or sulfur.

Flow is up to 15 GPM through 1 in. female NPT ports, at 25-80 psi, 40-100 F and pH 6-9. Capacity is 50,000 gallons or 12 months, roughly half that of the 20 in. models, so expect about twice as many cartridge changes. It is 16 by 8 by 18 in. per the product page's spec block and 21.8 lb, with no power or drain. The main product photo carries an SGS test-lab badge; no NSF/ANSI certification is stated.

Price was $173.99 at ispringfilter.com as of Oct 2026 (sale; 5% off $182.99). Warranty is 1 year limited with lifetime technical support, paid 3-, 5- and 10-year extensions and 30-day money-back. Install is DIY with a manual, video and wrench.

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iSpring WGB21B 2-Stage Whole House Water Filter well water whole-house filter

Specifications

Verified 2026-10-06. Fields the manufacturer does not publish are marked “Not stated”.

iSpring WGB21B 2-Stage Whole House Water Filter specifications
Model	WGB21B (10 in. x 4.5 in. cartridges: FP15B sediment + FC15B carbon block)
Type	Whole-house filter
Treats	Sediment; also chlorine (up to 99%, maker claim), taste and odor, VOCs, pesticides and herbicides, rust
Service flow	15 GPM'Up to 15 GPM' on the product page; the WGB & WDS series manual gives 'Flow Rate 3-15 GPM', 'Working Pressure 25-80 psi', 'Working Temperature 40-100F', 'pH Requirement 6.0-9.0'.
Capacity	50,000 gallonsUp to 50,000 gallons or 12 months.
Media / technology	5-micron polypropylene sediment cartridge + 5-micron coconut-shell CTO carbon block (10 in. x 4.5 in.)
Stages	2
Connection	1 in. FNPT
Installation	DIY'DIY Installation: Yes - comes with manual and step-by-step video guide'; 1 in. female NPT ports; wrench included.
Warranty	1-year manufacturer warranty'1-year limited warranty and lifetime technical support'; paid 3/5/10-year extended warranties offered. 30-day money-back.
Certifications	Not statedNo NSF/ANSI or other third-party certification is stated in the product page text or the WGB series manual. iSpring's main product photo carries an 'SGS' badge next to a 'Chlorine Removal' graphic (SGS is a test lab; this is a test claim, not a certification). WQA certified-product search (find.wqa.org) returned zero results for 'iSpring', 'iSpring Water', '123Filter', 'WGB32B' and 'RCC7AK' on 2026-10-06 (a control search for 'Culligan' returned listings). NSF certified-product database (info.nsf.org), searched 2026-10-06: iSpring Water Systems LLC (Cumming, GA) is listed only under NSF/ANSI 58 (RO systems) and NSF/ANSI/CAN 372 (WSP ...ARJ spin-down variants). WGB21B does not appear.
Dimensions	16 x 8 x 18 in. (product page spec block: 16.00 L x 8.00 W x 18.00 H); 10 in. x 4.5 in. housings
Weight	21.8 lb
Price	$174 (sale) at iSpring as of Oct 2026

Published features

Compact 2-stage 10 in. x 4.5 in. system for smaller homes
5-micron sediment pre-filter plus CTO carbon block
Up to 15 GPM with 1 in. NPT ports
50,000 gallon / 12-month capacity
No power or drain
DIY install with manual and video

Pros and cons

Pros

Lowest-cost whole-house cartridge system in this set
Compact footprint for tight utility spaces

Cons

50,000-gallon capacity means roughly twice as many cartridge changes as the 20 in. models
No iron, manganese, sulfur or bacteria treatment
1-year warranty; no NSF/ANSI certification

Our take

The WGB21B is the lowest-cost whole-house cartridge system here and fits tight utility spaces, which makes it a reasonable sediment and taste polisher for a small home or cabin with otherwise clean well water. Its 50,000-gallon capacity means frequent cartridge changes; if you have room and a larger household, the 20 in. WGB22B doubles the capacity for about $200 more.

Not sure it is the right size for your flow and your water test? Work through the sizing guide, or compare every system we cover on the best well water filtration systems (2026) list.

Where to buy

$174 (sale) at iSpring as of Oct 2026. Prices change; the links open the current listing.