BackflowNear Test-Due Reminder

Approved backflow testers in Walkersville, MD

21 backflow testing businesses work within 25 miles of Walkersville, 2 of them based in town. 4 have testers on Maryland's roster and 17 are on the approved tester list of 4 water utilities.

21 businesses within 25 miles

Backflow testing companies near Walkersville

What the badges mean
✓ MD Certified Backflow Tester Verified
A state roster lists at least one certified tester at this business, with a current certificate. The state sets the exam and renewal.
✓ MD Utility-Approved Tester Verified On the city list
The company is on a water utility's own approved list (the second badge names the list). That is the utility's approval, not a state license, and it counts for that utility.
3 certified testers
How many certified testers the roster lists at this business.
★ 4.8 (25 reviews)
The Google rating, shown as Google reports it. It does not change the order.

Order is by our quality score, never by payment. How we verify listings.

Are you a backflow testing company near Walkersville? One sponsor per county, clearly labelled. Sponsor this county

Warner Mechanical

90/100
✓ MD Utility-Approved Tester Verified On Anne Arundel County list Backflow Testing

217-A Monroe Ave, Frederick, MD 21701 · 7 mi from Walkersville

Call (301) 662-5387 Details Website
Verified Oct 2026 · Unclaimed listing

Ben Lewis Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 2.6 (38 reviews) On Anne Arundel County list Backflow Testing

23407 Frederick Rd, Clarksburg, MD 20871 · 18 mi from Walkersville

Call (301) 428-3900 Details Website
Verified Oct 2026 · Unclaimed listing

Charles A Klein & Sons, Inc

90/100
✓ MD Utility-Approved Tester Verified ★ 3.6 (57 reviews) On DC Water listOn Anne Arundel County list Backflow Testing

5220 Klee Mill Rd S, Sykesville, MD 21784 · 19 mi from Walkersville

Call (410) 549-6960 Details Website
Verified Oct 2026 · Unclaimed listing

Delmar Plumbing, LLC

80/100
✓ MD Utility-Approved Tester Verified ★ 3.3 (16 reviews) On DC Water list Backflow Testing

2 Hilton Ct, Gaithersburg, MD 20882 · 19 mi from Walkersville

Call (301) 774-2355 Details
Verified Oct 2026 · Unclaimed listing

Shary's Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 4 (29 reviews) On DC Water listOn WSSC Water listOn City of Rockville list Backflow Testing

3401 Kemptown Church Rd, Monrovia, MD 21770 · 23 mi from Walkersville

Call (301) 229-6695 Details Website
Verified Oct 2026 · Unclaimed listing

O'Conor Plumbing Services, LLC

90/100
✓ MD Utility-Approved Tester Verified ★ 4.5 (231 reviews) On DC Water listOn WSSC Water listOn Anne Arundel County listOn City of Rockville list Backflow Testing

19301 Mateny Hill Rd, Germantown, MD 20874 · 23 mi from Walkersville

Call (301) 540-5050 Details Website
Verified Oct 2026 · Unclaimed listing

Reliable Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 1 (3 reviews) On City of Rockville list Backflow Testing

21509 Ripplemead Dr, Gaithersburg, MD 20882 · 24 mi from Walkersville

Call (301) 948-1991 Details Website
Verified Oct 2026 · Unclaimed listing

The Drain Guys

90/100
✓ MD Utility-Approved Tester Verified ★ 4.7 (186 reviews) On City of Rockville list Backflow Testing

8041 Cessna Ave Ste 100, Gaithersburg, MD 20879 · 24 mi from Walkersville

Call (301) 867-7632 Details Website
Verified Oct 2026 · Unclaimed listing

Mallick Plumbing & Heating, Inc

90/100
✓ MD Utility-Approved Tester Verified ★ 4.9 (2436 reviews) On DC Water listOn WSSC Water listOn City of Rockville list Backflow Testing

7620 Rickenbacker Dr Ste L, Gaithersburg, MD 20879 · 24 mi from Walkersville

Call (301) 840-5861 Details Website
Verified Oct 2026 · Unclaimed listing

Harvey W. Hottel

90/100
✓ MD Utility-Approved Tester Verified ★ 4.1 (48 reviews) On DC Water list Backflow Testing

18900 Woodfield Rd, Gaithersburg, MD 20879 · 25 mi from Walkersville

Call (301) 461-0622 Details Website
Verified Oct 2026 · Unclaimed listing

Robert A. Tull, Inc.

80/100
✓ MD Certified Backflow Tester Verified ★ 2.8 (31 reviews) On WSSC Water listOn City of Rockville list Backflow Testing

7820 Airpark Rd, Gaithersburg, MD 20879 · 25 mi from Walkersville

Call (301) 948-2490 Details
Verified Oct 2026 · Unclaimed listing

Price reports

What a backflow test costs in Walkersville

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Published prices nationwide

$29.99 to $100 per assembly

Based on 14 published prices · Read Oct 2026 Prices testing businesses list on their own websites, from our cost guide. Listed prices, not what people paid.

Every published price, with its source: what a backflow test costs.

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Backflow testing questions in Walkersville

Where are the backflow testing businesses listed for Walkersville based?

21 backflow testing businesses are listed within 25 miles of Walkersville. 2 are based in Walkersville itself, 4 more within 15 miles and 15 further out, up to 25 miles away. Other towns with more than one listing: Gaithersburg (9), Frederick (3) and Monrovia (2). The closest is Gladhill Plumbing & Heating, Inc., 2 miles from Walkersville.

Which tester lists are the businesses near Walkersville on?

4 have testers on Maryland's roster and 17 are on the approved tester list of 4 water utilities.

How many of the backflow testing businesses near Walkersville have Google reviews?

18 of the 21 listed for Walkersville have 3 or more Google reviews. Mallick Plumbing & Heating, Inc has the most reviews, 2,436, with an average of 4.9 stars, as Google showed them at our last check.

Approved list: WSSC Water plumbing firms providing cross-connection related services, WSSC Water.

Approved list: Backflow Prevention Assembly Service Providers, DC Water.

Approved list: Anne Arundel County accepted plumbing companies providing backflow related services, Anne Arundel County Department of Public Works.

Approved list: City of Rockville certified backflow prevention testers, City of Rockville Department of Public Works.

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