Water & Sanitation: 4G SCADA Monitoring for 300 Distributed Stations

· 9 min read
9 min read
Sophie Durand
Sophie Durand
Technical Content Writer

Managing a network of pumping stations spread across 3,000 km² without a dedicated technician at each site—that’s the daily reality for water and wastewater operators. Here’s how 4G LTE and cloud-based monitoring are turning this challenge into an operational advantage.

The Challenge of Distributed Water Networks​

A drinking water or wastewater system involves hundreds of sites that must be monitored around the clock:

  • Pumping stations (lift, discharge, booster pumps)
  • Tanks and water towers (levels, quality)
  • Chlorination stations (dosage, residual chlorine)
  • Remote-controlled valves (shut-off, control)
  • Treatment plants (aeration, settling, filtration)

Most of these locations are isolated: no fiber-optic internet, no ADSL, and often in rural areas or forests. The only available means of communication is the cellular network.

For years, we had to make do with GPRS: 20 kbps data speed, high latency, and poor reliability. Today, 4G LTE is a game-changer.

Typical architecture: 300 stations on a 4G network​

Communications Infrastructure​

Typical Equipment per Station​

ComponentSpecification
GatewayEziwan Gateway, 35mm DIN rail
Power Supply12–48V DC (station power supply)
SIMDual SIM (Orange + SFR)
PLC ConnectionRS-485 Modbus RTU
AntennaOutdoor + low-loss cable (hollow sites)
Temperature-40°C / +75°C (unheated cabinets)

Modbus Data Collection: The Data That Matters​

Typical Pumping Station​

# Collected Modbus Registers — Pumping Station
slaves:
  - id: 1
    name: "Pompe principale"
    polling: 30s
    registers:
      - address: 0    # Pump Status (0=Off, 1=On, 2=Fault)
        name: etat_pompe
      - address: 1    # Operating hours (×10)
        name: heures_fonctionnement
        scale: 0.1
      - address: 2    # Instantaneous flow rate (m³/h × 10)
        name: debit_instantane
        scale: 0.1
      - address: 3    # Daily volume (m³)
        name: volume_journee
      - address: 10   # Downstream pressure (bar × 100)
        name: pression_aval
        scale: 0.01
      - address: 11   # Tarpaulin level (cm)
        name: niveau_bache
        
  - id: 2
    name: "Analyseur eau"
    polling: 300s
    registers:
      - address: 0    # Residual chlorine (mg/L × 100)
        name: chlore_residuel
        scale: 0.01
      - address: 1    # Turbidity (NTU × 100)
        name: turbidite
        scale: 0.01
      - address: 2    # pH (× 100)
        name: ph
        scale: 0.01

Configured Critical Alerts​

ParameterAlert ThresholdCritical ThresholdAction
Pump Failure—ImmediateOn-call SMS + email
Low tank level< 30%< 15%Email / SMS + remote shutdown
Residual chlorine< 0.1 mg/L< 0.05 mg/LOn-call SMS + ARS report
Downstream pressure< 1.5 bar< 1.0 barOn-call SMS
Connection lost> 5 min> 15 minEmail supervisor

Dual SIM: Ensuring Uninterrupted Service​

Water systems are critical infrastructure. Continuous monitoring is a regulatory requirement, not an option.

Out of 300 stations in rural and suburban areas, coverage is never consistent. Orange may be excellent in some places, SFR in others. And network outages do happen.

Eziwan Dual SIM Behavior — St-Étienne-du-Bois Pumping Station:

08:42  SIM1 Orange active — RSRP : -82 dBm — Latence : 28ms
09:15  SIM1 Orange signal degradation — RSRP: -101 dBm — 3 pings failed
09:15  → Bascule automatique SIM2 SFR
09:15  SIM2 SFR active — RSRP : -79 dBm — Latence : 31ms
09:16  SCADA Dashboard: Reconnection Detected (45-second outage)
12:30  SIM1 Orange revenue — RSRP : -80 dBm
13:00  → Switch back to SIM1 (Orange) (priority configured)

In a fleet of 300 stations, there are typically 15 to 30 SIM switches per month—which are completely transparent to the monitoring system.

Remote SCADA: Technicians Can Perform Maintenance Without Traveling​

VPN Access to PLCs​

Using the Eziwan OpenVPN/IPSec VPN, technicians can access field controllers directly:

# Technician logged in from the monitoring center
# OpenVPN/IPSec VPN active → local network access for each workstation

# Access to the Montceau-les-Mines Station's User Interface
http://192.168.15.100 → Local monitoring web interface

# Access to the Schneider TM3 PLC
# Logiciel EcoStruxure → IP : 192.168.15.10
# Diagnostics, parameter adjustments, fault reset

Average savings: 65% of service calls that previously required an on-site visit are now resolved remotely in less than 20 minutes.

Automatic Report for the ARS​

Eziwan can automatically generate the water quality reports required by the Regional Health Agency:

  • Residual chlorine history by station (export to CSV/PDF)
  • Compliance rate over the period
  • Quality alerts with timestamps and duration

See the local government use case → · Download the water monitoring guide →

Deployment: Lessons Learned from 300 Stations​

Sample Schedule​

PhaseDurationContent
On-site audit2 weeksInventory of access points, network coverage
ZTP configuration1 weekProfiles by station type
Pilot deployment1 month20 test workstations
Full-scale deployment3–4 monthsRemaining 280 workstations
Operator training2 daysDashboard, alerts, VPN access

ZTP Profiles by Station Type​

A single profile covers all stations of the same type. The configuration is deployed automatically as soon as the gateway connects:

  • Standard Pumping Profile: 85% of stations
  • Reservoir Quality Profile: 10% of stations (with analyzers)
  • Treatment-Plant-Profile: 5% of plants (extended configuration)

M-Bus Integration for Remote Meter Reading​

In water distribution networks, customer meters and automatic meter reading stations often use the M-Bus protocol (EN 13757-2) via cable or Wireless M-Bus 868 MHz (EN 13757-4) via radio. The Eziwan Gateway integrates into these architectures via an M-Bus/Modbus converter or directly via the Wireless M-Bus module:

# Example of a multi-meter remote meter reading configuration via M-Bus RS-485
mbus:
  baudrate: 2400                    # Standard M-Bus Speed
  slaves:
    - address: 1                    # Adresse M-Bus primaire (0-250)
      name: "Compteur eau zone A"
      manufacturer: "Itron"
      data_records:
        - drec: 0x01               # Total energy in m³
          name: volume_total
          unit: m3
        - drec: 0x02               # Instantaneous flow rate (m³/h)
          name: debit_instantane
          unit: m3h
        - drec: 0x06               # Cold Water Temperature
          name: temperature
          unit: degC
    - address: 2
      name: "Compteur eau zone B"
      manufacturer: "Kamstrup"

Advantage of M-Bus over 4-20 mA: M-Bus transmits the cumulative volume, instantaneous flow rate, temperature, and alarms (exceeding maximum flow rate, water return, module failure) in a single frame, without the need for separate analog wiring for each variable.

RPQS Compliance and Regulatory Data​

Operators under a Public Service Delegation (DSP) are required to produce an annual Report on Price and Service Quality (RPQS) for the delegating local authorities and the ONSB (National Observatory for Water and Sanitation Services).

RPQS performance metrics fed directly by Eziwan data:

RPQS IndicatorCodeEziwan Modbus Source
Microbiological Compliance RateP101.1Chlorine/turbidity quality meters
Linear Consumption Index (LCI)P104.3Pumped volumes + meter readings
Network Loss RateP106.3Volume distributed vs. metered volumes
Complaint RateP155.1N/A (CRM data)
Distribution Network EfficiencyP106.3Volume produced vs. distributed
DowntimeP151.1Logged pump/network alarm time

Automatically exporting this data as a CSV file from the Eziwan platform—including the calendar period and station ID—allows you to populate the RPQS tables directly without having to re-enter the data manually.

For stations subject to ARS monitoring (Regional Health Agency), quality data (residual chlorine, turbidity, pH) can be exported in a time-stamped format that complies with traceability requirements.

FAQ​

Does the transition from 2G GPRS to 4G LTE require replacing all PLCs? No. Field PLCs (Schneider TM3, Wago, Siemens, etc.) retain their RS-485 Modbus RTU serial protocols. Only the communication modem/router is replaced—the LTE gateway connects to the existing RS-485 bus. No changes to the PLC program are necessary.

What is the 4G LTE data usage of a standard pumping station? For a station that uploads 20 Modbus registers every 30 seconds via MQTT, data usage is in the range of 30 to 80 MB per month, including VPN. M2M IoT SIM cards with 100–500 MB/month data plans are generally sufficient. For a fleet of 300 stations, the SIM cost typically amounts to 8 to 15 € per site per month, all-inclusive.

How to Manage DDASS/ARS Reporting Requirements with 4G Monitoring? The Eziwan platform automatically exports water quality data (residual chlorine, turbidity, pH) in a timestamped CSV or PDF format, which can be used directly for DDARS/ARS reports. Alerts for threshold exceedances are logged with precise timestamps, which simplifies regulatory reporting.

Is Dual SIM really useful in rural areas with poor coverage? That’s exactly where it’s most useful. In rural areas, a single cell tower often covers your area—if it goes down (due to lightning, hardware failure, or maintenance), you lose network service. With two carriers and two separate cell tower networks, the probability of a simultaneous outage on both networks is very low (< 0.1% over the course of a year).

What kind of connectivity should be planned for a station in a complete dead zone? Apart from LTE coverage, alternatives exist: VHF/UHF radio (for water utility proprietary networks), LEO satellites (Starlink, Iridium, Eutelsat, OneWeb), or LoRaWAN if the municipality has a LoRa hub within range. Eziwan can be integrated with satellite backhaul solutions for truly remote sites.

Further Reading​

Conclusion​

Monitoring 300 water and wastewater treatment plants with two on-call technicians and no unnecessary travel—this is now possible thanks to 4G LTE, Dual SIM with automatic failover, and cloud-based monitoring tools.

The return on investment is quick: fewer on-call duties, less travel, easier regulatory compliance, and—most importantly—real-time insight into the status of your network, which you didn't have with GPRS.

Discuss your water/sewerage project → · View the SCADA monitoring demo →

Additional Resources​