Water Treatment Unit Maintenance Checklist
A maintenance checklist for water treatment units covering dosing system operation, chemical stock levels, system water testing, and compliance record-keeping for heating and cooling water circuits.
What is a water treatment unit maintenance checklist?
A water treatment unit maintenance checklist is a structured list of the 10 preventive maintenance tasks — covering visual, functional, cleaning, safety and record-keeping checks — that keep a water treatment unit running safely and reliably. It groups routine checks by frequency, from daily inspections to annual servicing, so FM teams and building engineers can plan and evidence preventive maintenance.
Core water treatment unit checks
- Check chemical stock levels in dosing tanks and order replacements as needed
- Verify automatic dosing pumps are operating and calibrated
- Check side-stream filter condition and clean or replace media
- Ensure COSHH data sheets are available for all chemicals on site
- Record water test results, chemical consumption, and dosing adjustments
What is a water treatment unit?
A water treatment unit manages the chemical condition of water in heating, cooling, or domestic water systems. This may include automatic chemical dosing pumps, monitoring sensors, filtration, and control equipment. Proper water treatment protects boilers, chillers, pipework, and heat exchangers from corrosion, scale, and biological contamination. It is a core requirement of BSRIA BG50/BG29 guidelines and often a condition of equipment warranties.
This checklist is one of 25 in our plumbing and water system maintenance checklists, covering pressurisation units, booster sets, storage tanks, TMVs and water treatment — pressure, hygiene and legionella control.
Typical Water treatment unit maintenance checklist
A practical starting point for planned preventive maintenance. Always refer to the manufacturer's O&M manual and site-specific requirements.
Visual Checks
- Check chemical stock levels in dosing tanks and order replacements as needed
- Inspect sensors and probes for fouling or drift
- Inspect all dosing lines and connections for leaks or blockages
Functional Checks
- Verify automatic dosing pumps are operating and calibrated
- Test system water quality — pH, TDS, inhibitor levels, dissolved metals
- Verify blowdown or bleed-off operation (open systems)
- Review alarm and fault log on the controller
Cleaning & Housekeeping
- Check side-stream filter condition and clean or replace media
Safety Checks
- Ensure COSHH data sheets are available for all chemicals on site
Record Keeping
- Record water test results, chemical consumption, and dosing adjustments
Download the free Water treatment unit maintenance checklist PDF
Get all 10 tasks as a printable PDF — free, no signup needed. Keep a copy in the plant room, attach it to work orders, or share it with your maintenance contractor.
Typical maintenance frequency
Suggested intervals for water treatment unit maintenance. Actual frequencies should follow manufacturer guidance and site-specific risk assessments.
Weekly
- •Check chemical stock levels
- •Verify dosing pump operation
Monthly
- •Test system water quality
- •Clean sensors and probes
Quarterly
- •Full water quality analysis
- •Check side-stream filter
- •Review dosing rates
Annually
- •Comprehensive water treatment review
- •Laboratory water analysis
- •Sensor calibration
- •Dosing pump service
Common faults and issues
Issues to be aware of when maintaining water treatment unit equipment.
Safety and compliance notes
Key safety considerations for water treatment unit maintenance. This is general guidance only — always follow OEM instructions, statutory requirements, and your organisation's safe systems of work.
Reference standards and frameworks
- United Kingdom
- HSE ACoP L8 and HSG274 for water hygiene
- North America
- ASHRAE Standard 188 (legionellosis risk management)
Frameworks commonly referenced when planning water treatment unit maintenance programmes. Always confirm the requirements that apply to your site and jurisdiction.
Managing Water treatment unit documentation with PM Assist
PM Assist helps FM and building operations teams search their O&M manuals and building drawings in seconds. Upload your water treatment unit documentation and ask questions like “What are the legionella control requirements?” or “When was the last water quality test?” — and get source-cited answers instantly.
See PM Assist answer questions about a real water treatment unit manual — try the live demo, no signup needed.
Take this checklist with you
Download the branded PDF, generate a custom version for your asset, or run AI search across all your building documentation.
Related free tools
Inspection checklists for this asset
Maintenance keeps the asset working; a statutory inspection records whether it currently passes. Both usually apply.
Further reading on water treatment unit maintenance
Compliance topics for water treatment unit maintenance
Frequently asked questions
Why is water treatment important for building services?
What is BSRIA BG50?
How often should system water be tested?
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- Source-cited answers for maintenance queries
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