Pre-Commissioning Water Treatment / Flushing Engineer

Our client is a trusted provider of commissioning and building services solutions, delivering specialist water treatment and flushing services to projects across data centres, pharmaceuticals, commercial, and healthcare sectors. With a strong focus on compliance, safety, and technical precision, they ensure systems are prepared to the highest standards before commissioning and handover.

About the Role

They are now seeking a skilled and experienced Senior Pre-Commissioning Water Treatment / Flushing Engineer to carry out the pre-commission cleaning, chemical dosing, flushing, and treatment of closed and open loop systems (including CHW, LTHW, condenser, and domestic water). This role is nationwide and critical to ensuring systems are delivered to specification, compliant with BSRIA BG29/BG50, and fully prepared for commissioning.

Key Responsibilities

• Perform pre-commission cleaning, dynamic and static flushing, chemical dosing, and sampling of HVAC and water systems in accordance with BSRIA and project specifications.
• Carry out closed and open loop water system flushing (CHW, LTHW, condenser, domestic hot & cold water).
• Conduct water quality testing, interpret results, and make treatment adjustments as needed.
• Complete on-site testing (pH, conductivity, iron, hardness, bacteria sampling Legionella, TVC, etc.).
• Maintain accurate documentation including flushing certificates, test results, and compliance records.
• Coordinate with mechanical and commissioning teams to ensure timely delivery of pre-commissioning works.
• Operate pumps, dosing rigs, side stream filters, and associated equipment.
• Ensure all works comply with HSE regulations and COSHH guidelines.
• Troubleshoot and resolve water quality or system performance issues.
• Attend client/site meetings and provide technical input as required.

Requirements

• Proven experience (5+ years) in water treatment, pre-commission cleaning, or mechanical flushing.
• Strong working knowledge of BSRIA BG29 & BG50 guidelines.
• Familiarity with HVAC systems, pipework layouts, strainers, valves, and test points.
• Experience handling treatment chemicals including inhibitors, biocides, and cleaning agents.
• Ability to use and calibrate basic water testing equipment.
• Excellent documentation, communication, and report-writing skills.
• Full, clean driving licence and willingness to travel.
• Safe Pass card required; additional site certs (e.g. confined space, MEWP) are a plus.

Preferred Experience

• Experience on large-scale projects (data centre, commercial, life sciences, industrial, or healthcare).
• Knowledge of closed loop, domestic systems, cooling towers, or cleanroom water treatment.
• Legionella awareness training or water hygiene qualification.
• Understanding of commissioning timelines and coordination with mechanical packages.
• Experience supervising or mentoring junior technicians or subcontractors.

Whats on Offer

• Competitive salary and allowances.
• Opportunities for certification and training (e.g. BSRIA, LCA).
• Exposure to high-profile projects across data centres, pharma, healthcare, and commercial sectors.
• Supportive team environment with clear progression opportunities.
• Company vehicle and travel expenses (where applicable).

Requirements

• Proven experience (5+ years) in water treatment, pre-commission cleaning, or mechanical flushing.
• Strong working knowledge of BSRIA BG29 & BG50 guidelines.
• Familiarity with HVAC systems, pipework layouts, strainers, valves, and test points.
• Experience handling treatment chemicals including inhibitors, biocides, and cleaning agents.
• Ability to use and calibrate basic water testing equipment.
• Excellent documentation, communication, and report-writing skills.
• Full, clean driving licence and willingness to travel.
• Safe Pass card required; additional site certs (e.g. confined space, MEWP) are a plus.

Preferred Experience

• Experience on large-scale projects (data centre, commercial, life sciences, industrial, or healthcare).
• Knowledge of closed loop, domestic systems, cooling towers, or cleanroom water treatment.
• Legionella awareness training or water hygiene qualification.
• Understanding of commissioning timelines and coordination with mechanical packages.
• Experience supervising or mentoring junior technicians or subcontractors.

Whats on Offer

• Competitive salary and allowances.
• Opportunities for certification and training (e.g. BSRIA, LCA).
• Exposure to high-profile projects across data centres, pharma, healthcare, and commercial sectors.
• Supportive team environment with clear progression opportunities.
• Company vehicle and travel expenses (where applicable).