Trade directory · Gaithersburg metro · Maryland

Plumbing contractors in
Gaithersburg, Maryland.

A public directory of licensed plumbing contractors serving greater Gaithersburg. Market data, licensing requirements, and cost benchmarks — updated continuously from public sources.

Licensed Establishments
2,066
U.S. Census Bureau
Peak Season
October through March (heating system issues, frozen pipes, holiday prep)
Market estimate
Avg. Response Time
24-48 hours for quotes, same-day for emergency calls
Operator average
§ A · Market rates

Common Job Costs

GAITHERSBURG-MD · LOCAL ESTIMATES
Service
Description
Cost Range
Drain cleaning
Typical range based on local drain cleaning jobs.
$150 – $400
Water heater installation
Typical range based on local water heater installation jobs.
$1,200 – $3,500
Toilet installation
Typical range based on local toilet installation jobs.
$300 – $800
Kitchen sink installation
Typical range based on local kitchen sink installation jobs.
$400 – $1,200
Sewer line repair
Typical range based on local sewer line repair jobs.
$2,500 – $8,000
Faucet replacement
Typical range based on local faucet replacement jobs.
$200 – $600
§ B · Regulatory

Licensing Requirements

MD
§1

Licensing Requirements

Maryland requires Master Plumber license through DLLR. Must pass state exam covering Maryland Plumbing Code, complete 4-year apprenticeship or equivalent experience, and maintain continuing education. Journeyman license available as intermediate step. License renewal every 2 years with 16 hours continuing education.

§2

Permit Requirements

Plumbing permits required through Montgomery County for most work. Water heater replacement, new fixtures, and re-piping need permits. Minor repairs like faucet replacement typically exempt. Permit fees range $50-200 depending on scope.

§3

Inspection Schedule

Rough-in inspection before covering work, final inspection after completion. Montgomery County requires 24-hour notice for inspections. Failed inspections require re-inspection fees.

§4

Insurance Minimums

Maryland requires minimum $300,000 general liability insurance for plumbing contractors. Workers compensation mandatory if employees. Bonding requirements vary by municipality.

§ C · Path to license

How to Get Licensed

5 STEPS
1

Complete apprenticeship or experience requirement

Complete 4-year plumbing apprenticeship program or demonstrate equivalent work experience under licensed plumber supervision

01/05
2

Submit application to DLLR

Submit Master Plumber license application to Maryland Department of Labor, Licensing and Regulation with required documentation and fees

02/05
3

Pass state examination

Pass Maryland Master Plumber examination covering Maryland Plumbing Code, safety regulations, and trade practices

03/05
4

Provide insurance documentation

Submit proof of required general liability insurance and workers compensation coverage if applicable

04/05
5

Obtain license and maintain renewal

Receive license and maintain through biennial renewal with 16 hours continuing education requirements

05/05
§ D · Field notes

About This Market

UPDATED APR 2026

Gaithersburg sits in Montgomery County where housing stock runs from 1970s-80s subdivisions to newer townhome developments. That means steady replacement work on aging systems plus new construction tie-ins. Competition's fierce with approximately 2066 licensed establishments statewide, but demand stays consistent from both residential service calls and commercial work from the I-270 corridor. Costs run higher than rural Maryland due to Montgomery County's affluent market and strict code requirements. Water heater replacements and drain issues drive most service calls, while bathroom renovations fuel the higher-ticket work. Montgomery County doesn't mess around with code enforcement, so you better know the Maryland Plumbing Code inside and out. Master Plumber license is non-negotiable for running jobs here. Permit process through the county runs smooth if your paperwork's clean, but inspectors will flag sloppy work fast. Winter's your money season when pipes freeze and water heaters fail. Keep emergency response capability or you'll lose customers to competitors who do. Local supply houses know the permitting quirks, so build those relationships early.

Data Sources
  • Licensed establishments count
    U.S. Census Bureau
  • Licensing requirements
    Maryland Department of Labor, Licensing and Regulation (DLLR)
  • Permit requirements
    Montgomery County Department of Permitting Services
  • Cost ranges
    Local market estimates
  • Insurance requirements
    Maryland Department of Labor, Licensing and Regulation
§ E · FAQ

Frequently Asked Questions

05 QUESTIONS
Q/01

What license do I need to work as a plumber in Gaithersburg, MD?

You need a Maryland Master Plumber license through the Department of Labor, Licensing and Regulation (DLLR). This requires passing the state exam and completing apprenticeship or equivalent experience.

Q/02

How much does a water heater installation cost in Gaithersburg?

Water heater installation typically ranges $1,200-$3,500 depending on unit type and complexity. Montgomery County's permit and inspection requirements add to baseline costs compared to other Maryland markets.

Q/03

Do I need permits for plumbing work in Gaithersburg?

Most plumbing work requires permits through Montgomery County. Water heater replacement, new fixtures, and re-piping need permits. Minor repairs like faucet replacement are typically exempt. Permit fees range $50-200.

Q/04

When is peak season for plumbing work in Gaithersburg?

October through March is peak season due to heating system issues, frozen pipe emergencies, and holiday preparation work. Emergency response capability is essential during winter months.

Q/05

What insurance do plumbers need in Maryland?

Maryland requires minimum $300,000 general liability insurance for plumbing contractors. Workers compensation is mandatory if you have employees. Additional bonding may be required by individual municipalities.

§ F · Directory

Plumbing contractors in Gaithersburg

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