First, the five regimes
Before choosing a sensor, know which record you are building. Every site below falls under at least one of these, and several fall under two:
| Regime | Who is regulated | The record it wants | Headline number |
|---|---|---|---|
| Blue Drop + SANS 241 | Water services authorities (drinking-water supply) | Microbiological and chemical compliance against SANS 241, process control, risk management | 26 of 958 systems certified (2023) — guide |
| No Drop | Water services authorities (losses and efficiency) | A credible water balance: system input, billed consumption, real and apparent losses | NRW 47.4%, 2.1 billion m³/yr (2023) — guide |
| Green Drop | Municipal wastewater systems | Works performance, final-effluent compliance, spill management, capacity | 47% of systems critical (2025) — guide |
| GN 665 General Authorisation / water-use licence | Anyone discharging to a river, dam, ground or land — works, mines, factories | Continuous discharge quality against general or special limits (COD 75/30 mg/L, SS 25/10, faecal coliforms 1000/0 per 100 mL…) | Limits table in our DWS compliance guide |
| Municipal trade-effluent bylaw | Factories and processors discharging to the sewer | Volume and strength (COD, suspended solids, pH) at the connection point — it is the basis of the bill | Charge = volume × strength — guide |
Municipal bulk supply and reticulation
The water services authority's core problem is arithmetic it cannot currently do: how much entered the system, how much was billed, and where the difference went. The 2023 No Drop report put national non-revenue water at 47.4% — 2.1 billion cubic metres a year out of 4.4 billion supplied — and certified only four authorities as excellent (Overstrand, the City of Cape Town, Midvaal and Swartland). The monitoring answer is structural: bulk meters at every input, reservoir levels telemetered, and the network cut into district metering areas whose inlet meters report minimum night flow — the number that turns "we lose water somewhere" into "this zone is leaking tonight". Pressure management follows as the lever that cuts bursts and background leakage once the zones exist.
Boreholes and wellfields
Farms, rural schemes, industrial self-supply and an increasing number of estates and businesses run on groundwater — and abstraction sits under water-use registration or licensing with volume conditions attached. The first sensor is the abstraction meter, telemetered so the monthly return is a report rather than a field trip; the second is water level in the borehole, because a falling static level is the early warning that the aquifer, the pump or a neighbour's new borehole is changing the economics. Pump current adds run-hours and dry-run protection. All of it lives on solar and buffers through outages — the shape described in our remote water monitoring page.
Reservoirs, towers and bulk storage
A reservoir with no telemetry produces two failures on a loop: overflows nobody sees at 03:00, and empty tanks nobody sees until the taps run dry. Level is the first sensor; inlet and outlet flow turn a level trace into a storage balance that reveals overnight leakage from the tank itself. The scenario recurs in surprising places — a recent enquiry from an air-force base described exactly this: an 11-metre tower, a mechanical meter, pressure gauges and a home-made transducer, needing level, metering and an offline-tolerant record. Tower, reservoir or farm dam, the instrumentation is the same: level, flow, and a record that works without a person present.
Pump stations — water and sewer
Water pump stations fail on power, on the pump, and on the suction side; sewer pump stations fail the same three ways and then overflow into a river, which is how a maintenance problem becomes a Green Drop finding and a pollution offence. The monitoring shape: mains presence, pump run and current per pump, wet-well or suction level, and — for sewer stations — high-level alarms with a communication path that survives cable theft. Our pump station overflow guide covers the sewer case, including inflow and infiltration during storms; the water case is the same hardware with a different consequence.
Water treatment works (WTW)
The Blue Drop audit examines a works' process control and its compliance monitoring, and the parameters it scores — turbidity, residual chlorine, flow, pH — are the ones continuous instrumentation records. A works that logs turbidity and chlorine residual online every few minutes, with alarms on excursion, walks into its audit with a year of evidence instead of a folder of grab samples. Our treatment works monitoring page covers the plant; SANS 241 covers what "compliant" means; the Blue Drop guide covers the audit.
Wastewater treatment works (WWTW)
Nearly half of South Africa's municipal wastewater systems were rated critical in the 2025 Green Drop report, and the failure is rarely mysterious: blowers that stopped, dissolved oxygen that collapsed, a final effluent nobody sampled until the regulator did. The instrumentation follows the process — inlet flow, dissolved oxygen and blower current in aeration, sludge blanket in clarifiers, chlorine residual at disinfection, and the final-effluent parameters GN 665 limits: COD, suspended solids, ammonia, faecal coliforms. Our WWTW monitoring guide walks the plant; the Green Drop guide shows which scoring areas move fastest.
Factories discharging to the municipal sewer
Food and beverage plants, abattoirs, dairies, breweries, textile dye-houses, metal finishers: anyone whose process water leaves through a municipal sewer is billed under a trade-effluent bylaw on volume times strength — typically COD, suspended solids and pH at the connection point — on samples the municipality takes. A continuous record of your own at that connection does two things: it lets you verify a bill computed from someone else's grab sample, and it catches the shock load from a CIP cycle before it becomes a penalty. The trade effluent guide covers the charge formula and pre-treatment proof; the solution page covers the instrumentation.
Factories and works discharging to the environment
Discharge to a river, dam, ground or land is a different regime entirely: a water-use licence with site-specific conditions, or the General Authorisation with its published general and special limits (COD 75 or 30 mg/L, suspended solids 25 or 10, faecal coliforms 1,000 or nil per 100 mL, pH windows, metals). The regulator's expectation is a continuous record against those numbers, and the practical instrumentation is flow plus the licence's named parameters — pH, conductivity, turbidity or suspended solids, and laboratory COD reconciled against an online surrogate. The DWS compliance guide carries the limits table; water-quality compliance is the solution.
Mines — dewatering, return water and discharge
A mine is a water-handling operation with an ore-processing hobby: dewatering volumes, tailings return-water balances, stormwater separation, and discharge or seepage under a water-use licence with conditions that read like a chemistry syllabus. Flow at every transfer point and licence-parameter monitoring at every discharge are the core; tailings facilities add level and seepage instrumentation under the engineer of record's design, covered in our tailings monitoring guide. The regulator-facing record is built the same way as for any environmental discharger — continuously, at the boundary.
Agriculture and irrigation schemes
Irrigation is South Africa's largest water use, and the scheme, the farm and the individual pivot each have a monitoring question: canal and offtake flows for scheme allocation, borehole abstraction against licence volumes, and soil moisture plus pivot and pump status for the crop itself. The return on instrumenting the farm side is documented in our irrigation ROI guide and the large-scale farm case study; the scheme side is bulk-metering and DMA logic transplanted to canals and pipelines.
Estates, body corporates and private schemes
A residential estate buys water on one bulk meter and sells it on hundreds of unit meters, and the gap between the two is its own non-revenue water — usually discovered as a levy dispute. Bulk-versus-sum-of-units reconciliation is the first instrument; unit-level smart or prepaid metering follows, with the choice between them covered in prepaid vs smart meters. Estates that also run boreholes, reservoirs and package treatment plants inherit the corresponding scenarios above in miniature, which is why they suit a single estate-wide telemetry layer.
Water shops and refill stations
The water shop's regulator is the municipal environmental health practitioner (Certificate of Acceptability under R638) and its standard is SANS 241, tested by a laboratory on a schedule. Its operational reality is that quality failures — skipped rinses, exhausted filters, chemical-tasting refills — happen between lab tests. Continuous TDS, flow and pressure monitoring with a customer-facing quality display is the scenario, documented in our start-up guide, the failure-mode research and the equipment price guide. A water-vending operator enquiry this month asked for exactly this: machines to monitor, unattended.
Hospitals, schools, hotels and facilities
Institutional sites carry a specific pair of risks: backup storage that must be full and turned over when municipal supply fails, and consumption that nobody allocates by building until the account arrives. Tank level with turnover tracking, sub-metering by block or department, and leak alarms on the night-flow pattern are the instruments; a hospital adds the treatment-plant and discharge scenarios above if it runs its own. Facilities of this kind usually fold water into a wider building telemetry layer with energy and HVAC.
Catchment management and the regulator's own view
The catchment management agency or DWS regional office faces the mirror image of every scenario above: many dischargers, many abstractors, one river, and Section 19 duties to prevent pollution with evidence that stands up. River gauges and in-stream quality stations, solar-powered at outfalls and rural works, build the oversight record — the subject of our catchment monitoring guide and the regulatory oversight solution.
The map on one table
| Site type | First measurement | Regime | Failure it prevents |
|---|---|---|---|
| Municipal reticulation | DMA inlet flow → minimum night flow | No Drop | Invisible leakage, unbilled water |
| Bulk supply & reservoirs | Level + inlet/outlet flow | No Drop / service delivery | Overflows, empty tanks, tank leakage |
| Boreholes & wellfields | Abstraction meter + water level | Water-use registration / licence | Over-abstraction, pump burn-out, licence breach |
| Water pump stations | Pump current + suction level + mains | Service delivery | Silent pump failure, dry running |
| Sewer pump stations | Wet-well level + pump state + comms alive | Green Drop, pollution law | Overflow to river, spill fines |
| Water treatment works | Turbidity + chlorine residual + flow | Blue Drop, SANS 241 | Unsafe water reaching consumers, audit failure |
| Wastewater treatment works | Dissolved oxygen + blower current + final effluent | Green Drop, GN 665 | Process collapse, non-compliant discharge |
| Factory → sewer | Flow + COD surrogate + pH at connection | Trade-effluent bylaw | Over-billing, shock-load penalties |
| Factory / works → environment | Flow + licence parameters continuously | GN 665 / water-use licence | Licence breach, directive, prosecution |
| Mines | Flow at every transfer + discharge quality | Water-use licence, GISTM (tailings) | Unaccounted water, seepage, licence breach |
| Farms & irrigation schemes | Abstraction + soil moisture + pump status | Licence volumes, scheme allocation | Over-irrigation, energy waste, allocation disputes |
| Estates & body corporates | Bulk vs sum-of-units reconciliation | Own levy economics | Unrecovered water cost, levy disputes |
| Water shops & refill | TDS + flow + filter pressure drop | R638 COA, SANS 241 | Quality failures between lab tests, shutdowns |
| Hospitals, schools, hotels | Storage level/turnover + sub-metering | Continuity of service, own budget | Empty backup tanks, unallocated consumption |
| Catchment / regulator | River gauges + in-stream quality | NWA Section 19 | Pollution without evidence, unattributed discharges |
Three rules that hold across every row
- Measure at the boundary. Where water changes hands or crosses a licence line — the bulk meter, the connection point, the outfall, the borehole head — is where a continuous record has legal and financial weight. Instrument there first.
- Whoever holds the count holds the argument. A laundry bill, a trade-effluent charge, an NRW figure, a licence return — each is decided by a number someone measured. Independent measurement is worth more than any dashboard feature, which is why we sell neither water nor meters for a supplier: our numbers have no side.
- Design for the site you actually have. Load shedding, no fibre, vandalism, cable theft and distance are the South African defaults. Solar power, local buffering and LoRaWAN or 4G links chosen per site are not extras — they are what keeps the record continuous, and a record with gaps loses the argument it was built to win.
Where to go deeper: water management solutions (the delivery) · the six water-monitoring jobs · non-revenue water · DMA design · DWS discharge compliance · trade effluent · Green Drop · Blue Drop · which sensor measures what.