Water Safety Plan
Guide
Treatment Processes
– Pump Operation
Version 1, Ref P10
January 2014
Citation: Ministry of Health. 2014. Water Safety Plan Guide:
Treatment Processes – Pump Operation, Version 1, ref p10.
Wellington: Ministry of Health.
Published in January 2014
by the Ministry of Health
PO Box 5013, Wellington, New Zealand
ISBN: 978-0-478-42758-5 (print)
ISBN: 978-0-478-42759-2 (online)
Previously published in 2002 as Public Health Risk Management
Plan Guide: Treatment Processes – Pump Operation, Version 1, ref
p10. This publication’s title and any reference within the text to ‘public
health risk management plan’ were changed in January 2014 to
reflect the December 2013 legislation change of the term ‘public
health risk management plan’ to ‘water safety plan’. No other
changes have been made to this document.
This document is available at: www.health.govt.nz
This work is licensed under the Creative Commons Attribution 4.0 International
licence. In essence, you are free to: share ie, copy and redistribute the material in any medium or
format; adapt ie, remix, transform and build upon the material. You must give appropriate credit,
provide a link to the licence and indicate if changes were made.
Contents
Introduction
1
Risk Summary
2
Risk Information Table
3
Contingency Plans
7
Water Safety Plan Performance Assessment
9
Ref P10
Version 1, January 2014
Water Safety Plan Guide:
Treatment Processes – Pump Operation
iii
Introduction
Pumps are used in a number of ways in a water supply: providing pressure; controlling
pressure fluctuations; moving water and dosing chemicals. This Guide is concerned with the
management and operation of the three main categories of pumps:
Transmission pumps:
These move water from the source through the supply system.
Bore pumps:
These pumps draw water out of bores or wells; they may be down
the bore hole or on the surface.
Process pumps:
These are used to dose chemicals and to pump water to equipment
that checks water quality (monitoring).
If an event occurs during pump operation (ie, a pump doesn’t work properly), the following
could happen:

if there are fluctuations in water pressure because a transmission pump fails, or does
not operate in a way that avoids water hammer, backflow can occur so that germs or
chemicals may get into the water and cause sickness

if there are fluctuations in water pressure because a bore pump fails, backflow can
occur so that germs or chemicals may get into the water and cause sickness

if chemicals or disinfectants are not dosed or monitored properly because a process
pump fails, germs that are not killed or removed or chemicals that are incorrectly dosed
may cause sickness.
The operation of pumps can present risks to the health of supply staff. These are
acknowledged, but are not discussed further as such risks are the subject of health and safety
in employment legislation.
Correct pump operation helps to reduce public health risk from a number of supply activities
(see P1, P4, P5, P6, P7, P8, and D2 series of Guides, and Guides P3, P9 and D1).
For every pump in a supply, records should be kept of:

pump identification number

pump type

condition factor

maintenance schedule.
Ref P10
Version 1, January 2014
Water Safety Plan Guide:
Treatment Processes – Pump Operation
1
Risk Summary
The two events creating the greatest risk with pumps are the failure of a transmission pump
which can lead to backflow and pipe failure caused by pressure fluctuations and water
hammer (P10.1), and the failure of a dosing pump to dose chemicals at the correct rate
(P10.2).
The most important preventive measures are:

to have duplicate pumps for critical operations (P10.1.1, P10.2.1)

to have devices in place to reduce water hammer (P10.1.1)

to have preventive maintenance programmes (P10.1.1, P10.2.1).
(References in parentheses are to the Risk Information Table.)
2
Water Safety Plan Guide:
Treatment Processes – Pump Operation
Ref P10
Version 1, January 2014
Risk Information Table
Reliable information about water quality is essential for the proper management of a water
supply. Knowledgeable and skilled staff are also essential for minimising the public health
risks associated with water supplies. Please read the staff training (Guide G1) and the
monitoring guides (Guide G2). While we haven’t pointed out every detail of how these
documents are linked with the present document, the links are many and are important.
Abbreviations: DWSNZ – Drinking-Water Standards for New Zealand; MAV – Maximum acceptable value – see
DWSNZ:2000, FAC – free available chlorine.
Causes
Preventive measures
Checking preventive measures
Corrective action
Signs that action
is needed
What to check
Event: CHANGES IN PRESSURE, OR WATER HAMMER (PRESSURE SURGES), SUCK CONTAMINANTS
INTO THE WATER
Possible hazards: Germs and chemical contaminants.
Level of risk: High
(See Guides P2 and D2.2 for additional causes of this event.)
P10.1.1

Transmission
pump failure
due to
mechanical
failure or
overload.
In addition to
the possibility of
contaminants
being sucked
into the water
by back flow,
water hammer
can also cause 
pipe failure.
Preventive maintenance
programme in place:
– regular inspections
– lubrication
– seal replacement
– leaks repaired
– corroded
components
replaced
– annual ammeter
tests
– daily visual
inspection, etc.
Planned maintenance
programme for
replacement of
components as per
manufacturer’s
recommendations.

All pumps itemised and
maintenance schedule
followed.

Duplicate pumps for
critical applications.

Use duplicate pumps
alternately (provides a
check that both are
functioning and will not
need to be overhauled
at the same time).

Align and secure all
pump-linked pipework,
valves and fittings
according to standard
practice.
Ref P10
Version 1, January 2014

Flows.

No water.

System
pressure.


Reservoir
levels.
Reservoir levels
are difficult to
maintain.

Pump
maintenance
log.
Frequent pump
breakdowns.

Frequency of
unacceptable
pressure drops
in the system.

Maintenance
log not kept.

Non-compliance
with
DWSNZ:2000.


E. coli.

FAC.

Revise, or put in
place
maintenance
schedule.

Review service/
duty periods of
duplicate
pumps (time in
operation: time
on standby).

Carry out
residual
disinfection in
the distribution
zone if not
presently done.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
3
Causes
Preventive measures
Checking preventive measures
Corrective action
Signs that action
is needed
What to check
Event: CHANGES IN PRESSURE, OR PRESSURE SURGES (WATER HAMMER) SUCK CONTAMINANTS
INTO THE WATER cont’d
P10.1.1 cont’d

Install devices to lessen
water hammer should it
occur, eg:
– surge tanks
– air chambers
– slow-closing check
valves
– surge suppressors.
P10.1.2

Carry out biennial
inspection of power
source, connections
and electrical
equipment.
No water
because of
pump failure
due to power
failure.



P10.1.3
No water
because of
pump failure
due to flooding
or other
damage.
4


Set up standby
generator to cut in
automatically when
main power fails.
Run standby generator
monthly.
Locate pumps above
likely flood levels.
Correctly align and bolt
pumps to plinth.
Protect pump(s) from
the weather.

Flows.

No water.

System
pressures.


Reservoir
levels.
Reservoir levels
are difficult to
maintain.

Pump
maintenance
log.
Frequent pump
breakdowns.

Frequency of
unacceptable
pressure drops
in the system.


E. coli.

FAC.

Maintenance
log not kept.

Non-compliance
with
DWSNZ:2000.

Prepare and
follow
inspection
schedule.

Modify standby
generator to
allow automatic
cut in.

Carry out
residual
disinfection in
the distribution
zone if not
presently done.

Relocate
pumps.

Flows.

No water.

System
pressures.


Reservoir
levels.
Reservoir levels
are difficult to

maintain.


Pump
maintenance
log.
Frequent pump
breakdowns.
Provide cover
for pump(s).

Frequency of
unacceptable
pressure drops
in the system.


Maintenance
log not kept.
Disinfect the
distribution
zone if not
presently
disinfected.

Non-compliance
with
DWSNZ:2000.


E. coli.

FAC.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
Re-align pumps
and secure.
Ref P10
Version 1, January 2014
Causes
Preventive measures
Checking preventive measures
Corrective action
Signs that action
is needed
What to check
Event: INCORRECT CHEMICAL DOSING LEADS TO POOR TREATMENT
Possible hazards: Germs and chemical contaminants.
Level of risk: High
P10.2.1

Process pumps
do not add the
correct dose of
chemical.
P10.2.2
Process pumps
supplying water
to monitoring
instrumentation
fail.
Schedule preventive
maintenance,
particularly replacement
of elastomeric parts:
diaphragms; tubing etc.,
as per manufacturers
recommendations.

Calibrate dosing pumps
for expected duty.

Ensure pumps are fit for
the purpose, eg.,
corrosion resistant.

Provide duplicate
pumps for critical
functions.

Turbidity.

E. coli.

FAC.

Chemical
usage.

Chemical type
being dosed.

Coagulation
process (if
appropriate).

Non-compliance 
with
DWSNZ:2000.

Signs of
ineffective
coagulation.

Visually check pumps
daily.

Check stroke and speed
settings for manual
pumps.

Strainers on pump lines
to remove debris.

Flow rates to

instrumentation.

Clean strainers
regularly.

Condition of
strainers.

Ensure pumps are fit for 
the purpose.

Check required flow

rates are within the
range recommended by
the manufacturer.
Schedule preventive
pump maintenance.
Ref P10
Version 1, January 2014
Replace
pump(s) with
one appropriate
for the chemical
being dosed
and its
concentration.

Obtain standby
pump (critical
functions).
No, or irregular, 
flow to
instrumentation.

Fluctuating
readings from
instrumentation.
Put strainers in
place.
No
maintenance
programme in
place.
Use day tanks to reduce
risk of overdosing.





Turbidity.
E. coli.
Review dosing
programme.
Difficulty
maintaining a
chlorine
residual in the
treated water.
Daily check amount of
chemical used.





FAC.
Put
maintenance
schedule in
place.
Non-compliance
with
DWSNZ:2000.


Maintenance
log not kept.

Strainers
clogged.
Replace pump
with a unit
having
specifications
that match
requirements.
Prepare and
follow
maintenance
schedule.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
5
Causes
Preventive measures
Checking preventive measures
Corrective action
Signs that action
is needed
What to check
Event: CHANGES IN PRESSURE FROM THE BORE SUCK CONTAMINANTS INTO THE WATER
Possible hazards: Germs and chemical contaminants.
Level of risk: Moderate-high1

P10.3.1
Failure of the
bore pump(s).

1
6
Monitor bore
performance either
directly or using an
observation bore.
Schedule a preventive
maintenance
programme for bore
pumps, and a planned
maintenance
programme for the
overhaul of pumps.

Monitor flow from the
bore.

Monitor system
pressure.

Bore flow.


System
pressure.
Bore pumps
stop.


E. coli.
Reduced, or no,
flow from

bore(s).


Reduced
pressure in
distribution

zone fed
directly from the
bore.

Non-compliance
with
DWSNZ:2000.

No
maintenance
log kept.
Investigate bore
pump
performance.
Put
maintenance
programme(s)
in place.
Disinfect the
distribution
zone if not
presently
disinfected.
If the water is disinfected after being drawn from the bore, or the water is pumped into a reservoir before
reticulation, the consequences of the event will not be as severe as when the bore water is pumped directly into
the distribution system.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
Ref P10
Version 1, January 2014
Contingency Plans
If an event happens despite preventive and corrective actions you have taken, you may need
to consult with the Medical Officer of Health to assess how serious a problem is.
Event – Contamination gets in the water because of pump failure
Indicators:
Required
actions:
Responsibility:

Reservoir levels difficult to maintain.

Pump failure.

Flow significantly reduced.

Pressure decrease or fluctuations.

Elevated levels of turbidity or chemical determinands.

In 100 ml samples of water, E. coli is continually detectable, or
is present at elevated levels (more than 10 per 100 ml).

Increased chlorine demand.

Widespread illness in the community linked to the water supply.

Follow the actions given in Figure 3.2 or 3.3 (whichever is
appropriate) of the DWSNZ:2000.

If chemical contamination is suspected, monitor concentrations
of the suspected determinand and follow the actions given in
Section 4.4.1 of DWSNZ:2000.

Identify the reason for pump failure, repair or use standby pump,
and plan for long term preventive measures.

Ensure that chlorine residuals of more than 0.2 mg/L can be
maintained throughout the distribution system.

Review laboratory results and take further samples if necessary.

Record cause of system failure and steps taken to correct.

Modify your water safety plan if necessary.
Manager designated responsible for the water supply.
Ref P10
Version 1, January 2014
Water Safety Plan Guide:
Treatment Processes – Pump Operation
7
Event – Germs not killed or removed during treatment because of pump failure
Indicators:
Required
actions:
Responsibility:
8

Visual observation of ineffective coagulation.

No, or low, chlorine residual leaving the treatment plant.

Pump failure.

Elevated levels of turbidity or chemical determinands.

In 100 ml samples of water, E. coli is continually detectable, or
is present at elevated levels (more than 10 per 100 ml), in water
leaving the treatment plant.

Increased chlorine demand, which may not be met.

Widespread illness in the community linked to water supply.

Follow the actions given in Figure 3.2 or 3.3 (whichever is
appropriate) of the DWSNZ:2000.

Identify the reason for pump failure, repair or use standby pump,
and plan for long term preventive measures.

Ensure that chlorine residuals of more than 0.2 mg/L can be
maintained throughout the distribution system.

Review laboratory results and take further samples if necessary.

Record cause of system failure and steps taken to correct.

Modify your water safety plan if necessary.
Manager designated responsible for the water supply.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
Ref P10
Version 1, January 2014
Water Safety Plan Performance
Assessment
To make sure that your supply’s water safety plan (formerly known as a Public Health Risk
Management Plan, PHRMP) is working properly, periodic checks are needed. The overview
document outlines what needs to be done. The following table provides the detailed
information for checking this particular supply element.
What to measure or
observe:

System pressure and/or flow rates.

Pump maintenance log books.

Determinands affected by the performance of treatment
processes using process pumps.

Consumption of treatment chemicals (no or little change
may indicate pump failure).

Faecal indicators (E. coli).

FAC.

Reservoir levels.
Follow the protocols set out in DWSNZ:2000 where appropriate.
A number of factors may affect these measurements or
observations. A good understanding of the operation of the
water supply will help in interpreting the results.
How often:
What to do with the
results:
Ref P10
Version 1, January 2014

For the monitoring frequencies for FAC and E. coli
measurements see DWSNZ:2000 Section 3.3.2.

System pressures, and maintenance logbooks should be
checked at a frequency considered necessary by the
manager responsible.

Record results to meet legislative requirements or to allow
water safety plan performance assessment. The WINZ
database is good for this.

The collected data need to be periodically reviewed to see
whether problems with this supply element are
developing. This should be done as frequently as the
manager responsible considers necessary to minimise risk
to public health arising from this supply element.

Should this review show any unusual incidents, indicate
that proper procedures are not being carried out, highlight
poor laboratory results or indicate that poor water quality
is reaching customers, then review the procedures for the
management and operation of pumps.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
9

Responsibility:
10
Evaluate the monitoring results, and any actions taken as
the result of having to implement a contingency plan, to
see if the water safety plan needs modification – eg,
preventive measures are up to date; the contingency plan
steps are still adequate; and changes to the management
and operation of pumps are recognised in the plan.
Manager designated responsible for the water supply.
Water Safety Plan Guide:
Treatment Processes – Pump Operation
Ref P10
Version 1, January 2014