Water Treatment Plant & Pump Station SCADA Electrical SWMS
SWMS variants reference your state’s WHS legislation. Instant download after payment.
Electrical and SCADA work at water treatment plants and potable water pump stations is high risk construction work in New South Wales because it is carried out on or near energised electrical installations, in or near confined spaces including wet wells and valve pits, in areas that may have a contaminated atmosphere from chlorine and dosing chemicals, in or near water involving a risk of drowning, and at heights on wells, hatches and structures. Section 291 of the Work Health and Safety Regulation 2025 (NSW) captures all five categories, and a safe work method statement is required under section 299. SafeWork NSW is the regulator. **This SWMS covers potable and treated-water facilities. Sewage and wastewater pump stations are deliberately excluded** — a sewage wet well brings hydrogen sulphide and a biologically active atmosphere this document is not authored for, and that work requires its own.
**The defining hazard of SCADA work is that the plant can be operated from somewhere else.** A pump at an unmanned station starts on a telemetry command from a control room kilometres away, on a level signal from a reservoir it has never seen, or on a schedule nobody on site knows about. Local isolation of the control system is not isolation of the pump: the motor starter answers to the RTU, and the RTU answers to a network that has no idea anybody is standing at the machine. Every energy isolation in this document therefore isolates at the **power** level, never the control level — and every forced SCADA point is treated exactly as an injected instrument signal is treated: as an act that operates real plant at the far end of a wire, in front of people who do not know a test is running.
The second cluster is the water and what treats it. A clear-water wet well is still a confined space and still a drowning hazard — **clean water drowns exactly as effectively as dirty water** — and a well can fill on a remote command, which is why inflow isolation includes the telemetry. Chlorine is the treatment chemical, and chlorine gas is **heavier than air**: it collects in the dosing room's low points, in pits and at stairwell bases, and the evacuation is up and out. These sites are also routinely unmanned and remote, which turns an ordinary injury into a survival problem: nobody is coming past.
Hazards identified
14 hazards covered, sorted by priority.
Fatality — a pump starts on a telemetry command from a control room kilometres away with a worker on it
Fatality — a forced SCADA point starts a pump or drives an actuator onto a person elsewhere on the network
Fatality or catastrophic burns — arc flash at the MCC or switchboard in a damp switchroom
Fatality — electrocution in a pump station that is damp by design, where water and supply share the structure
Fatality — chlorine exposure in a dosing room, with the gas collecting in the low points people evacuate through
Fatality — asphyxiation, engulfment or entrapment in a wet well, valve pit, reservoir or dosing tank
Fatality by drowning — a fall into a well, channel or reservoir, or a well filling on a remote command
Fatality — a fall from an open hatch, well access ladder, elevated walkway or tank top
Fatality or catastrophic asset failure — telemetry, alarms or level protection left isolated at an unmanned station running blind
Serious chemical burns and chlorine gas generation — hypochlorite contact, or hypochlorite meeting acid
Fatality — an ordinary injury at a remote unmanned site becomes unsurvivable because nobody is coming past
Fatality or serious injury — stored energy released from pressurised mains, surge vessels or pump volutes
Permanent noise-induced hearing loss from pumps, motors and blowers in hard-surfaced structures
Musculoskeletal injury from handling pumps, panels, cable drums and batteries at sites with stairs, ladders and hatches
Control measures
Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.
- 1**Isolate and lock out at the POWER level — the motor's supply at its starter or circuit breaker — never at the control level**, because the starter answers to the RTU and the RTU answers to a network that does not know anyone is on site. Treat local/remote selectors and control-system inhibits as convenience settings, not isolation, and prove rotation impossible physically rather than from an HMI.
- 2**Take the target plant out of service at the control system before any point is forced** — forcing a point is operating the plant from the engineering workstation, and the energy is at the far end of the network. Trace the point's downstream function first, obtain the control room's acknowledgement before every force and again on release, and record every force on a register with no force left in place at the end of a shift.
- 3Obtain an arc flash risk assessment establishing incident energy and approach boundaries at the actual board, verify upstream protection, close the door for any test that can be done closed, and treat moisture ingress or corrosion as a stop-and-refer condition.
- 4Complete installation, termination and verification dead under Part 4.7 Div 4 ss.154 & 157, provide RCD protection on circuits and test supplies, select equipment for the damp situation to AS/NZS 3000, never work energised while standing in water, and pump down flooded pits before electrical work.
- 5Work only with the fixed chlorine detection and ventilation in service, never in a dosing room whose detection is out, and recognise that detection is mounted LOW because chlorine is heavier than air. **Evacuate UP and OUT — away from pits, stairwell bases and low points where the gas collects** — and treat a faint chlorine smell as a finding to report, never as normal background.
- 6Treat every wet well, valve pit, reservoir and dosing tank as a confined space under Part 4.3 Division 2 — permit, atmospheric testing before and continuously during entry, forced ventilation, a standby person who does not enter, and rescue in place before entry. **Isolate every inflow including the telemetry, because a well can fill on a remote command.**
- 7Keep hatches and grates closed and secured except for the immediate task, isolate inflows at the telemetry so the level cannot rise on a remote command while work is at the water, never work alone at open water, and provide rescue equipment appropriate to the water body at the work area.
- 8Work from ground and closed hatches wherever the task allows, barricade or attend every open hatch for the whole time it is open, never use a ladder as a working platform for two-handed work, and treat wet and algae-slicked surfaces as slippery by default.
- 9Plan the work so alarms and protective functions stay in service, cover any unavoidable isolation with agreed alternative monitoring, record every isolation at the moment it is applied, and **functionally re-verify and obtain the control room's acknowledgement of restoration before the crew leaves** — high-level, low-level and fault alarms are the only thing watching an unmanned site.
- 10Isolate and depressurise dosing lines before any work near them, never break into a dosing line under this SWMS, confirm safety shower and eyewash to AS 4775 within reach and operational, and **never bring hypochlorite into contact with acids, because the reaction releases chlorine gas**.
- 11**Require a minimum crew of two at unmanned stations — no lone work** — prove communications at the site before work starts because these sites sit in coverage gaps, keep a check-in schedule with automatic escalation on a missed call, and follow the utility's access and notification procedure so the operator knows the site is occupied.
- 12Keep electrical work clear of pressurised pipework, never crack, drill or fix into a pressure-bearing component, recognise that surge vessels and mains remain pressurised when pumps are stopped, and report any leak or weep to the operator rather than investigating it.
- 13Assess noise exposure against the exposure standard, test and read from outside the pump room where instrumentation allows, and **identify the gas alarm's visual indication before hearing protection goes on** — protection that masks the alarm defeats another control.
- 14Use the station's davit, gantry or lifting eye for pumps and heavy items, lower loads through hatches by line rather than passing hand to hand, use two-person handling for panels, batteries and drums, and never carry on a ladder.
Applicable Codes of Practice
The installation, protection and verification requirements, including the additional requirements for damp and wet situations that a pump station is built of.
Confined space classification, atmospheric testing, entry permits, standby arrangements and non-entry rescue for wells, pits, reservoirs and dosing tanks.
The benchmark for isolation, testing for dead and the conduct of low-voltage work in an environment that is damp by design.
The eyewash and safety shower provision required wherever chlorine and hypochlorite dosing equipment is worked on or near.
The benchmark for entry permits, testing, ventilation, standby and non-entry rescue — including the isolation of every inflow, telemetry included.
The benchmark for chlorine and hypochlorite as hazardous chemicals, including the workplace exposure standards and emergency planning.
High-Risk Construction Work triggered
Open hatches, well access ladders, elevated walkways and tank tops are worked at throughout. An open hatch in a floor is the site's most reliable fall, and beneath many of them is water.
Wet wells, valve pits, reservoirs and dosing tanks are entered for cabling, instrumentation and pump work. Restricted egress, potentially depleted or chlorinated atmospheres, and the ability of the space to fill on a remote command make these confined spaces under Part 4.3 Division 2.
Switchboard, MCC and motor circuit work is carried out with the station's supply present, and commissioning cannot be done dead. The category is sharpened here by remote operation: the plant answers to a network, so an isolation that stops at the control system is not an isolation at all.
Chlorine gas and hypochlorite off-gassing are present wherever water is treated. Chlorine is heavier than air, so it accumulates in exactly the pits, low points and stairwell bases that a person would evacuate through — the atmosphere hazard and the egress hazard are the same hazard.
Work is carried out over, beside and at open wells, channels and reservoirs at depth. Clean water drowns exactly as effectively as dirty water, and the level can rise on a telemetry command while a person is at it.
Carrying out high risk construction work without a compliant SWMS is an offence under the Work Health and Safety Regulation 2025 (NSW). A remote-start fatality is investigated on the question of what the PCBU isolated and why: SafeWork NSW's interest is whether the method distinguished power-level isolation from control-level inhibits, because a SWMS that accepts a local/remote selector or a SCADA tag-out as isolation has documented a control that does not exist. Where alarms or telemetry are left inhibited at an unmanned station and an asset or environmental failure follows, the isolation register is requested alongside the SWMS, and a discharge arising from an unmonitored overflow attracts POEO Act 1997 (NSW) liability independently of any WHS outcome.
Who this is for
- →Electrical contractors delivering pump station and water treatment plant projects
- →SCADA, telemetry and controls contractors commissioning RTUs and PLCs on water networks
- →Water utilities and councils engaging contractors for electrical and control work on potable water assets
- →Principal contractors requiring a compliant SWMS before work at a treatment plant or pump station
- →Maintenance contractors carrying out switchboard, motor circuit and instrumentation work at unmanned stations
What you receive
- ✓A complete 14-hazard SWMS authored for NSW, citing the WHS Regulation 2025 (NSW), section 291 and section 299
- ✓Risk ratings across initial and residual, with the controls that bridge them written in full
- ✓Controls structured across all five levels of the hierarchy — elimination, substitution, engineering, administrative, PPE
- ✓Remote start and forced SCADA points authored as the two lead hazards — isolate at power level, never control level
- ✓Chlorine's heavier-than-air behaviour written into both the atmosphere control and the evacuation direction
- ✓Inflow isolation that includes the telemetry, because a well can fill on a remote command
- ✓The no-lone-work rule for unmanned remote sites, authored as a control and reflected in the workers section
- ✓An explicit scope statement excluding sewage and wastewater pump stations, and why
- ✓A PPE schedule mapped task by task to the applicable Australian Standard
- ✓An emergency response section written for chlorine release, person-in-the-water, confined space and electrical contact
- ✓A worker sign-on register and an HRCW checklist left blank for the PCBU to complete
- ✓Editable Microsoft Word format, ready to add project and PCBU detail
Worked example
An electrician is replacing a failed level probe in the wet well of a rural potable water pump station. It is an unmanned site, an hour from town. He isolates the pump at the local control panel — selector to LOCAL, control power off, his lock on it — and enters the well. The control room, forty kilometres away, sees a reservoir level fall and issues a transfer command. The RTU passes it to the starter. The pump runs. The electrician is not killed by the pump. He is killed by what the pump does: the well's level draws down and the inflow valve, sequenced with the transfer, opens to replenish it. The well fills. He is in it, in a harness with no retrieval line rigged, and the standby person is a phone in a ute at the gate because the site is unmanned and the job was 'twenty minutes'. The investigation finds every element of the isolation was performed and none of it was an isolation. The LOCAL selector is a request to the control system; the control system had no obligation to honour it and, on this RTU's configuration, did not. The control power he switched off ran the panel's indication, not the starter's coil. His lock was on a device that never carried the energy. Nobody in the control room knew the site was occupied, because nothing required them to be told. SafeWork NSW's position was that the SWMS described a control-level isolation as though it were an energy isolation, and that a document written for SCADA-controlled plant which does not distinguish the two has not described the plant it covers. This SWMS isolates at the power level, requires the control room's acknowledgement before work, requires every inflow — telemetry included — isolated before entry, and requires two people at every unmanned site, because the second man is the only rescue that exists an hour from town.
Related legislation
- Work Health and Safety Act 2011 (NSW) — primary duty of care (s19), consultation (s47), notifiable incidents (ss35–38), industrial manslaughter (s26A)
- Work Health and Safety Regulation 2025 (NSW) — HRCW (s291), SWMS content and requirement (s299), SWMS review (s302)
- Work Health and Safety Regulation 2025 (NSW) — Part 4.3 Division 2 — confined spaces (wet wells, valve pits, reservoirs, dosing tanks)
- Work Health and Safety Regulation 2025 (NSW) — Part 4.7 Division 4, sections 154 and 157 — prohibition on energised electrical work
- Protection of the Environment Operations Act 1997 (NSW) — discharge offences, engaged where unmonitored overflow follows an inhibited alarm