Waterspecialist WS638B Water Filter Review
Our verdict
The Waterspecialist WS638B is one of the most affordable replacement filters in the category at $13.59 for a two-pack, while still carrying NSF 42 and NSF 372 certifications. A 4.6-star average from 509 reviews makes it a credible budget choice.
Check price on AmazonBest for
Cost-conscious buyers who want NSF-certified filters at a very low per-filter cost and have a compatible refrigerator model.
Skip if
You want a high review volume for additional confidence, or need a larger pack count to reduce reorder frequency.
- Certification Nsf 42&372
- Pack 2
- Dimensions 2.2 X 4.3 X 7.4 In
- Priced 51% below the category median ($27.99 across 140 tracked models)
Our scorecard
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Owner rating4.6/5
4.6 average across 509 owner ratings
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Popularity1.8/5
509 owner reviews, fewer than most models here
The overall score is owner satisfaction weighted by how many reviews back it, so a high rating from few reviews counts for less. The bars below show where this model stands against the other water filtration: replacement filters, under-sink and reverse osmosis systems, filter pitchers, water dispensers, coolers, faucet filters and softeners we track in this category on price, popularity and size. Context, not marks against it, and our read of the data, not a lab test.
Overview
At $13.59 for two filters, the WS638B comes in at roughly $6.80 per filter, which is among the lowest prices for an NSF-certified replacement filter in this format. Waterspecialist is an established brand in the aftermarket filter segment with a strong compatibility catalog across major refrigerator manufacturers.
The filter carries NSF 42 certification, which covers aesthetic impurities like chlorine taste and odor, and NSF 372 certification, which addresses lead-free material compliance in the filter's construction. The two certifications together confirm both filtering performance and material safety standards.
Measuring 2.2 x 4.3 x 7.4 inches, the WS638B is a compact form factor suited to push-in or twist-in refrigerator filter housings. With 509 reviews at 4.6 stars, the feedback base is solid for this price tier.
Pros
- NSF 42 certified to reduce aesthetic impurities such as chlorine taste and odor
- NSF 372 certified for lead-free material compliance
- Very low per-filter cost at roughly $6.80 each
- 4.6 stars from 509 reviews shows consistent buyer satisfaction
Cons
- Two-pack format means more frequent reorders compared to three or four-pack alternatives
- Capacity in gallons is not listed in available specs
- Compatible refrigerator models require verification before purchase
Specifications
| Certification | Nsf 42&372 |
|---|---|
| Pack | 2 |
| Dimensions | 2.2 X 4.3 X 7.4 In |
Performance notes
The WS638B is certified to NSF 42, which is designed to reduce aesthetic impurities including chlorine taste, chlorine odor, and certain particulates. NSF 372 certification addresses lead-free compliance in the filter's construction materials. These two certifications are common in the category and provide a clear baseline for what the filter is independently verified to address. Capacity is not stated in available specs, so replacement timing should follow the manufacturer's recommendations.
What buyers say
509 ratings averaging 4.6 stars is a reliable signal for a budget filter. Buyers in this price range typically have high sensitivity to fit and value, and the score suggests Waterspecialist delivers on both for most compatible refrigerator models.
Similar water filtration: replacement filters, under-sink and reverse osmosis systems, filter pitchers, water dispensers, coolers, faucet filters and softeners to consider
Frequently asked questions
What does NSF 42 certification mean on the Waterspecialist WS638B?
NSF 42 is a standard that covers aesthetic effects, primarily the reduction of chlorine taste, chlorine odor, and certain particulates. A filter certified to NSF 42 has been independently tested and shown to be designed to reduce these aesthetic impurities under the conditions specified in the standard. It does not cover health-effect contaminants, which fall under NSF 53 or other standards.
What is NSF 372 certification?
NSF 372 is a material safety standard focused on lead-free compliance. It verifies that the materials used in the filter's construction meet requirements for limiting lead content. This certification applies to the filter components themselves rather than the water passing through, adding confidence that the filter housing and media do not introduce lead into the filtered water.
Is the Waterspecialist WS638B the right choice for budget buyers?
At roughly $6.80 per filter with dual NSF certifications and a 4.6-star average, the WS638B is a strong value option. The main steps before purchasing are confirming your refrigerator model is compatible and checking the manufacturer's replacement interval guidance, since gallon capacity is not published in the available spec data.