Plumbing Listings

The listings assembled within Waterfiltration Authority document water filtration and related plumbing service providers operating across the United States. Each entry represents a business or licensed professional operating within the water filtration, water treatment, or connected plumbing services sector. The Water Filtration Directory Purpose and Scope page establishes the classification framework that governs which providers appear here and under what category. Readers navigating these listings include homeowners, commercial facility managers, property inspectors, and procurement professionals seeking qualified contractors.

How to read an entry

Each listing record presents provider information in a structured format. The fields displayed follow a consistent hierarchy across all entries:

1. Business name — the registered trade name or legal entity name as filed with the relevant state authority.
2. Service category — one of the defined classification types: water filtration installation, water treatment systems, reverse osmosis systems, whole-house filtration, point-of-use filtration, or water softening and conditioning.
3. License type and number — where available, the state-issued plumbing or specialty contractor license. Licensing requirements vary by state; the How to Use This Water Filtration Resource page outlines how license data is sourced and formatted.
4. Geographic service area — expressed as a state, metropolitan statistical area (MSA), or county-level coverage zone.
5. Contact information — business address, phone, and website as submitted or verified through public business registries.
6. Verification status indicator — a flag denoting whether the listing has been reviewed against a named public source within the past 12 months.

Entries do not include pricing data, customer reviews, or performance ratings. Those elements fall outside the reference function of this directory.

What listings include and exclude

Included:

• Licensed plumbing contractors who hold an active state-issued plumbing license and offer water filtration installation or maintenance as a documented service.
• Water treatment specialists holding a Water Quality Association (WQA) Certified Water Specialist (CWS) credential or equivalent certification issued by a recognized credentialing body.
• Businesses registered with a state contractor licensing board that list water softening, filtration, or purification as a primary trade category.
• Providers serving residential, light commercial, and industrial water filtration applications where the work falls under a plumbing or specialty contractor classification.

Excluded:

• Unlicensed handyman services, even where water filtration work is offered.
• Equipment-only retailers and distributors who do not perform installation or maintenance.
• Home warranty companies and third-party service administrators.
• Providers operating exclusively outside the United States.
• Companies whose primary business is HVAC or general contracting where water filtration is incidental and unspecified.

The boundary between a licensed plumbing contractor and a water treatment equipment dealer reflects the regulatory distinction enforced by most state licensing boards. Plumbing work — including the installation of filtration equipment connected to potable water supply lines — falls under the scope of the Uniform Plumbing Code (UPC), published by the International Association of Plumbing and Mechanical Officials (IAPMO), and the International Plumbing Code (IPC), maintained by the International Code Council (ICC). Both codes require that connections to potable water systems be performed by a licensed plumber or under licensed supervision.

Verification status

Listings carry one of three verification status designations:

• Verified — the license number, business name, and state of record have been confirmed against a named public source, such as a state contractor licensing board database, within the past 12 months.
• Pending verification — the listing has been submitted or identified but has not yet completed cross-reference against a public licensing authority.
• Unverified — the entry is included based on business registry data or public directory sources, but no active license confirmation has been completed.

Verification does not constitute an endorsement. It confirms only that the license reference provided corresponds to an active record in a public state database at the time of review. State licensing authorities — such as the California Contractors State License Board (CSLB), the Texas State Board of Plumbing Examiners (TSBPE), and equivalent bodies in all 50 states — maintain the authoritative record of licensure status. Professionals and service seekers are directed to consult those primary sources for current standing.

Permit and inspection compliance is a separate dimension from licensing. Municipalities and counties with adopted versions of the UPC or IPC require permits for new filtration system installations and for modifications to existing potable water supply lines. Permit records are maintained at the local jurisdiction level and are not reflected in these listings.

Coverage gaps

The directory does not represent complete national coverage. Documented gaps include:

• Rural and frontier service areas — providers operating in counties with populations below 10,000 are underrepresented. State licensing databases in 12 states do not publish machine-readable license data, which limits automated verification for those jurisdictions.
• Specialty industrial filtration — providers serving industrial process water, pharmaceutical-grade filtration, or municipal water treatment fall under distinct regulatory frameworks (including EPA Safe Drinking Water Act requirements) and are outside the primary scope of these listings.
• Emerging credentials — the water treatment credentialing landscape includes certifications issued by the Water Quality Association, NSF International, and state-level training programs. Providers holding newer or state-specific credentials may not yet be classified consistently across all entries.
• Recent business changes — business closures, license lapses, and address changes between verification cycles create gaps that are addressed during scheduled update reviews.

The Water Filtration Listings index provides a full browsable view of current entries across all service categories and geographic regions. Requests to add, correct, or flag a listing are handled through the process described on the contact page.