Water Pipe Pressure Monitoring: Fewer Leaks and Bursts

Low-pressure complaints come from the housing on the hill, while pipes in the low-lying area near the reservoir burst twice in a month. Both happen on the same network, and they share a root cause: pressure nobody is managing. Too low in one place, too high in another, and nobody knows the numbers through the day.

Water pipe pressure monitoring makes those numbers visible. With sensors in the right places and data logged continuously, network operators can bring excess pressure down without hurting service, cut leakage, and reduce bursts. This guide covers why pressure matters so much, where sensors go, why night pressure is the one to watch, and which alarms to set.

Why pressure drives leaks and bursts

Water escapes faster from a hole or crack when pressure is higher. In water loss management, this is usually written as leak flow proportional to pressure raised to the power N1. For a hole of fixed size, N1 is about 0.5. For cracks that open wider as pressure rises, especially in plastic pipes, N1 can reach 1 to 1.5 or more. The real value differs between networks and needs measuring in the field.

An illustrative calculation for a 20% pressure reduction:

N1 value	Leak flow remaining	Leakage reduction
0.5	about 89%	about 11%
1.0	80%	20%
1.5	about 72%	about 28%

Pressure also affects how often pipes burst. Sustained high pressure loads old pipes and joints, and brief surges (transients or water hammer) from valves closed too fast or pumps tripping can go far above normal working pressure. So it is not just average pressure that needs managing, but its swings too.

Night pressure: when leaks run fastest

During the day, high flow causes friction losses in the pipes, so pressure at the far end of the network drops. At night demand falls, friction almost disappears, and pressure across the zone rises towards its static level. The result is that leaks run fastest when almost nobody is using water.

That is why pressure should always be logged alongside night flow. A rise in night flow can mean a new leak, or simply higher night pressure. Calculating leakage from night flow is covered in our article on leak detection with Minimum Night Flow; this one focuses on the pressure side. Night pressure is also an opportunity: many zones can take lower pressure at night without any customer noticing.

Where to place pipe pressure sensors

• Zone inlet, usually downstream of the pressure reducing valve (PRV) or pump. It shows the pressure supplied to the zone.
• Critical point, the lowest-pressure location in the zone, usually the highest or furthest point from the source. Pressure here decides whether customers are still served, and sets how far inlet pressure can be reduced.
• Average zone point (AZP), a location representing the zone's average pressure. Night pressure here is used to relate pressure to leakage.
• Lowest elevation, where static pressure is highest and pipes are under most stress.
• Near large customers or pressure-sensitive sites such as hospitals or industrial estates.

Elevation matters a lot: every 10 metres of height difference changes static pressure by about 1 bar. Record the elevation of each measuring point so readings can be compared properly.

Choosing sensors and logging intervals

• Range to cover the highest possible pressure, including static night pressure, with headroom for surges.
• Output: 4-20 mA or RS-485 Modbus RTU are common on industrial pressure transmitters and easy for a gateway to read.
• Power and communication. Critical points are often at the roadside with no power and no cabled network. Choosing a link is covered in our article on LoRaWAN vs cellular vs wired.
• Logging interval. One to five minutes is enough for daily patterns and night pressure. Transients last seconds or less, so they need high-speed loggers for a dedicated survey.

Pressure management in water networks

1. Divide the network into zones with metered inlets, so each zone's pressure can be set on its own.
2. Fit PRVs at zone inlets. A fixed-outlet PRV is the first step. A time-modulated PRV lowers pressure overnight, and a flow-modulated PRV matches pressure to demand through the day.
3. Run pumps to demand, for example with speed control, instead of pumping at full pressure all day.
4. Control transients by opening and closing valves slowly and avoiding sudden pump trips.
5. Reduce in steps and measure. Check every setting change against critical point pressure and night flow over the following days.

Pressure alarms worth setting

• Critical point below the service limit: customers at the end of the network start running short.
• Night pressure above target: usually a PRV not working or a bypass left open.
• Sudden pressure drop: together with a jump in zone inflow, very likely a burst.
• Large repeated swings: an unstable PRV or a pump cycling on and off.
• Data stops arriving: a sensor or link problem, and that point is no longer watched.

Use two levels, warning and critical, and add a time delay so brief spikes do not trigger alarms. The principles are in our guide to setting sensor alarm thresholds.

Things to keep in mind

• Minimum pressure must still be met. Planning criteria and service standards set a minimum residual pressure at the furthest point, and firefighting needs count too. Reduce pressure to that limit and no further.
• Lower pressure reduces leaks; it does not remove them. Finding and fixing leaks is still needed.
• Intermittent supply behaves differently. When pipes refill, trapped air and surges are common, so pressure patterns cannot be read like those of a continuously pressurised network.
• Fitting sensors to pressurised pipes needs a tapping and isolation valve, and is a job for competent technicians.

Frequently asked questions

What is the ideal water pressure in a network?

There is no single figure for every zone. Pressure is enough when the critical point meets the applicable minimum service level and firefighting needs, with a sensible margin. Pressure above that mainly adds leakage and burst risk.

How is pressure monitoring different from pressure management?

Monitoring measures and records pressure. Pressure management adjusts it through PRVs, pumps, and zoning based on that data. Monitoring comes first, because without data nobody knows how far pressure can safely come down.

How many sensors does a zone need?

At least the inlet and the critical point. Add the average zone point and the lowest point to quantify how pressure affects leakage more accurately.

Water pipe pressure monitoring with INCLUDE

InWater monitors clean water distribution by zone: flow and supply per zone, reservoir and tank levels, water quality, leak detection with Minimum Night Flow, zone ranking to prioritise inspections, and network alarms. Valves can also open and close automatically by schedule or threshold.

Pressure transmitters with a Modbus RTU output are read through IncludeGateways and sent over 4G or LoRa, so a roadside critical point needs no data cable back to the office. Pressure data lands on the same INCLUDE platform as your InWater data, so it can sit next to zone flows on a custom dashboard. Each point can have tiered safe ranges (optimal, warning, critical), and its alarms can be forwarded to Telegram. Pressure itself is still regulated by PRVs and pump controllers in the field; the platform's data shows whether their settings are right.