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Servicing the fastest growing region of Western Australia, Knowles Plumbing is one of the oldest businesses of its type in Australia, having been established just after World War II. It is an autonomous arm of the Sanwell Group.

Knowles Plumbing currently operates from Welshpool in Perth and undertakes contracts in small to medium to large-scale commercial Projects, including high-density residential construction projects throughout Perth, and in the South West of Western Australia.

Our construction team specialises in hydraulic contracts with our experienced team of project managers, construction supervisors and foreman – we are well structured to manage all hydraulic contracts.

Our dedicated and highly competent team work cohesively together to deliver the best results for all projects undertaken.



Knowles Plumbing specialise in Hydraulic Services for Commercial Construction, Industrial, and Resource Sectors and provide services to Health Care Facilities, Office and Residential developments, Shopping Centres, Schools, Defence, Industrial, Refurbishments, Country Projects, including infrastructure services of deep sewerage, stormwater drainage, water supply mains and gas services.


The Knowles Team has a wide range of skills and experience in the Hydraulic Sector including but not limited to;

  • Sanitary Plumbing


  • Sewer, waste and vent – both in ground and suspended


  • Grey Water Systems & Septic Systems


  • Trade Waste & Grease Traps


  • Stormwater drainages systems


  • Siphonic Roof Drainage


  • Water Supplies (potable, non-potable, RO, hot and warm water)


  • Hot water systems


  • Tanks and Pumps


  • Gas services


  • Fit Out Projects


  • Fire systems including fire hydrants, fire hose reels, boosters, tanks and pumps


  • Backflow Prevention


  • Design and Construct Projects

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Knowles Plumbing has a dedicated, loyal and professional team that will collectively work together to deliver positive outcomes.


The company only employs key personnel and key subcontractors with a proven track record with experience, or who are capable of producing quality workmanship of a high standard.

The collection of long-term employees is a testament to our commitment to provide a positive working culture that involves internal promotion and training.

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Brad Ralph

General Manager

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Sean Needham

Project Manager / Estimator

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John McRae


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Josh Edmonds


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Cale Wilson


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Russell Tough





Head Office

37 Division Street,

Welshpool WA 6106


Tel: (08) 9258 3200

Email: Click here


To apply for a job with Knowles Plumbing, please send a cover letter together with your C.V. to: Click here