Water filtration system

iSpring WGB21B 2-Stage Water Filtration RO Compatible Replacement Filters

The iSpring WGB21B 2-Stage Whole House Water Filtration System features large sumps fitted for 4.5" x 10" filter cartridges. Developed for residential applications, the filters installed in the system should remove chlorine from water as well as sediment, rust, pesticides, herbicides, industrial solvents, and various other contaminants. Find the compatible replacements below along with recommended change-out schedule.

See the replacement schedule

Compatible parts

Everything that fits the iSpring Water Systems WGB21B

Pentair

Pentair DGD-5005 Cartucho de filtro de sedimentos 5 micras 4,5 "x 10" 155357-43

(17)

$25.99

Certificado NSF 42

Pentair

Filtro de bloque de carbón Pentair EP-BB 5 micras 4,5" x 10" 155548-43

(9)

$67.99

Reduce el cloro, el sabor y el olor.

Certificado NSF 42

Replacement filter info

Your replacement schedule

Each stage of the iSpring Water Systems WGB21B, the exact part that fits it, and when to change it.

Stage 1: Sediment filter

Part 155357-43, Pentair DGD-5005 Cartucho de filtro de sedimentos 5 micras 4,5 "x 10" 155357-43 $25.99

Every 1–6 months
Stage 2: Carbon block filter

Part 155548-43, Filtro de bloque de carbón Pentair EP-BB 5 micras 4,5" x 10" 155548-43 $67.99

Every 6–12 months

Manuals & instructions

Manuals and guides

iSpring WGB21B Whole House Filtration System Manual 5-21 PDF, opens in a new tab

FAQ

iSpring Water Frequently Asked Questions

How often should I replace my iSpring RO filters and membrane?

How long your iSpring compatible filters and membrane last will depend on your household water useage and water quality. Reverse osmosis filters generally last 6-12 months, and the RO membrane about 2 years. Learn more about how to change your RO filters.

How do I order replacement filters for my iSpring RO system?

Start by clicking on the photo of your iSpring system on https://ispwaterproducts.com/collections/ispring-water-systems. From there, you can add the needed filters to your cart. In some cases, you can save time by ordering all of the needed filters in one "filter kit" (not available for all iSpring models).

What contaminants will iSpring Reverse Osmosis systems remove?

iSpring filter systems can eliminate a broad spectrum of contaminants. Utilizing advanced filtration technologies, iSpring systems can effectively reduce common pollutants from water including pesticides, sulfates, fluoride, nitrates, lead, pharmaceuticals, arsenic and more. The RO system's carbon filter will also remove chloramines and chlorine.

Learn more about what contaminants can be removed with reverse osmosis filtration.

How often should I replace filters in my iSpring RO system?

Most iSpring systems require sediment and carbon pre-filters every 6–12 months, a post-carbon filter annually, and the RO membrane every 2 years, depending on usage. Replacement schedules apply across popular models like the iSpring RCC7 and RCC7AK. For guidance, see ESP Water’s RO Filter Replacement Instructions.

Which replacement filter kits fit my iSpring RO model?

Each iSpring system has a specific filter set. For example, the PH100 6-Stage and RO100 5-Stage use different replacement cartridges than the PureDrop RTW5. Always match your model number when selecting from ESP Water’s iSpring model pages.

How do I know which iSpring filters are compatible with my system?

Locate your system’s model number, then match it to the correct replacement collection. ESP Water supports models ranging from the RCC7P Pumped RO System to the US31 3-Stage System. If unsure, use the Identify My RO System article to confirm compatibility.

What signs indicate my iSpring RO filters need replacing?

Signs include slow water flow, poor taste or odor, cloudy water, or rising TDS levels. Slow flow is a common indicator of clogged pre-filters. For troubleshooting, see ESP Water’s article on Why RO Water Flow Is Slow, then choose replacements for your model (e.g., RCC7P-AK or RCC7).

Can I install iSpring RO replacement filters myself?

Yes — iSpring systems are designed for DIY filter changes using standard housings and clear instructions. Shut off water, relieve pressure, and swap filters following the system manual. For general steps, visit ESP Water’s How to Change RO Filters & Membranes guide. Replacement filters are available for models like the WCB32C and WGB22B.

Are iSpring RO filters interchangeable with other filtration systems?

Some iSpring systems use standard 10-inch cartridges, making them compatible with other RO brands, but always verify filter type and stage order. Systems such as the WGB12B or WGB21B use specific sediment and carbon formats. When in doubt, reference ESP Water’s Identify My System tool.

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