THAILANDSICThailand Standard Industrial Classification

TSIC Activity

43221

Water plumbing and drain laying installation

ประกอบกิจการ บริการรับต่อท่อประประปา และติดตั้งอุปกรณ์ประปาทุกชนิด

What this activity covers

Companies in this sector install and maintain water supply and drainage systems for buildings and construction projects.

  • Water supply systems — Installation of hot and cold water pipes
  • Drainage systems — Installation of sewage disposal and drain pipes
  • Sanitary equipment — Installation of plumbing connections and sanitary fixtures
  • Fire extinguishing systems — Installation of systems using water jets
  • Maintenance services — Repairs and upkeep of plumbing systems
  • Automatic watering systems — Installation of plant watering systems

What companies here also do

Seen in real company registrations under this code — beyond the official definition, so licensing may differ.

  • Design services — Designing plumbing and electrical systems
  • Consulting services — Providing advice on water systems
  • Importing materials — Importing pipes and construction materials

Not included here

  • Construction of water supply and drainage/sewage systems for public utilities. See activity 42201.

Foreign ownership

List 3: Restricted, FBL/BOI route availableinherited from 43

Construction, except construction of infrastructure providing basic public services in public utilities or transport that requires special apparatus, machinery, technology or expertise, and except other categories prescribed in ministerial regulations

The infrastructure carve-out is subject to a minimum foreign capital requirement, subject to capital thresholds, verify current figures.

FBA B.E. 2542, List 3 (10)Routes: Foreign Business Licence, BOI promotion, US Treaty of Amity

Auto-mapped, verify against the Act. These TSIC mappings are indicative, not legal advice; the schedules of the Foreign Business Act B.E. 2542 are the authority. See the full foreign ownership reference.

Industry at a glance

as of 23 ก.ค. 69

The whole registered industry under this activity, every registration year, from the DBD DataWarehouse.

1,575
active companies operate here
฿8.8Bregistered capital, combined
฿27.5B
Sector revenue · 2025
+45% since 2023
฿1.2B
Net profit · 2025
789 profitable
202320242025

net profitrevenue

Foreign investment

new registrations · 2026 YTD
2%of new registered capital is foreign-held
฿2.0M foreign฿105.6M Thai

Almost entirely Thai-held — little foreign capital enters here.

New in 2026

68+21.4%

registrations, YTD

Registered capital

฿8.8B+25.4%

since year-end

Largest by revenue

Latest filed-year revenue, not a multi-year total

  1. 1Italthai Engineering Co., Ltd.฿5.1B
  2. 2Rolling Concept Innovation Co., Ltd.฿1.7B
  3. 3Wong Siam Construction Co., Ltd.฿1.4B
  4. 4IRY INTERNATIONAL CO., LTD.฿908.8M
  5. 5TECH-TOP ENGINEERING (THAILAND) CO., LTD.฿740.6M

Largest by registered capital

  1. 1Italthai Engineering Co., Ltd.Bangkok฿1.3B
  2. 2Wong Siam Construction Co., Ltd.Bangkok฿1.2B
  3. 3Hydro Engineering Co., Ltd.Bangkok฿361.7M

Source: Department of Business Development DataWarehouse. Financial figures are combined totals of companies that filed statements; revenue and profit shown for the latest three reporting years.

Companies registered since 2022

Browse all

New DBD registrations under this activity since 2022, the period the registry snapshot covers, not the full historical register.

431
Registered
since 2022
411
Still active
20
Dissolved
฿1.0M
Median capital
of active

New registrations per year

2022peak 118 in 20242026

Largest active companies by registered capital

Source: Department of Business Development (DBD) new-registration records, 2022 to present. Counts cover companies first registered in that window, reflect the latest snapshot load, and may lag the live register.

Emerhub

Restricted activity? There is usually a route.

Emerhub structures foreign-owned companies around FBA restrictions: Foreign Business Licence applications, BOI promotion, and compliant shareholding structures. Talk through your case before you commit to one.

Talk to Emerhub Thailand