What Standards Must Drinking Water Meet?
Safe drinking water must comply with national and international water quality standards covering a defined set of physical, chemical, and microbiological parameters. In China, the primary standard is GB5749-2006 (Standards for Hygiene of Domestic Drinking Water). Internationally, the WHO Guidelines for Drinking-water Quality set globally referenced benchmark values.
The most commonly monitored compliance parameters include:
| Parameter |
GB5749 / WHO Guideline Limit |
| Turbidity |
≤1 NTU (≤3 NTU under special conditions) |
| pH |
6.5–8.5 |
| Residual Chlorine |
≥0.05 mg/L at end-point; ≤4 mg/L |
| TDS (Total Dissolved Solids) |
≤1,000 mg/L |
| Conductivity |
Reference indicator |
| Dissolved Oxygen |
Process indicator for treatment quality |
Monitoring these parameters continuously — rather than relying on weekly or monthly grab samples — is the only reliable way to detect compliance exceedances as they occur and protect public health in real time.
Recommended Kainafu Sensors for Drinking Water Compliance
1. KNF-1004L — Turbidity Sensor (ISO 7027)
Why turbidity matters: Turbidity above 1 NTU in treated drinking water signals filter failure, floc carryover, or sediment intrusion — and may indicate microbial contamination risk. It is one of the strictest and most universally enforced drinking water limits.
The KNF-1004L uses an 860 nm laser source compliant with ISO 7027. With a detection limit of 0.005 NTU — 200 times more sensitive than the regulatory limit — it reliably catches even minor filter breakthrough events before non-compliant water reaches consumers.
| Specification |
Value |
| Range |
0–100 NTU / 0–1,000 NTU |
| Detection limit |
0.005 NTU |
| Accuracy |
2% or ±0.05 NTU |
| Repeatability |
≤1% |
| Protection |
IP68, 60 m depth |
| Output |
RS-485 + 4–20 mA |
2. KNF-101PRO — pH / ORP Sensor
Why pH matters: Drinking water outside the 6.5–8.5 pH range is both a compliance violation and a safety concern — low pH accelerates pipe corrosion, leaching lead and copper into the supply; high pH reduces chlorine disinfection efficiency and causes taste complaints.
The KNF-101PRO measures pH (±0.02 accuracy) and ORP simultaneously, supports both submersible and pipeline installation, and uses a ceramic sand core junction that resists biofouling through the long service periods typical of drinking water distribution monitoring.
| Specification |
Value |
| pH range |
0–14 |
| Accuracy |
±0.02 pH |
| ORP range |
±1,000 mV |
| Installation |
Submersible or pipeline |
| Protection |
IP68, 6 bar / 50 m |
| Output |
RS-485 Modbus RTU |
3. KNF-1005D — Platinum Method Residual Chlorine Sensor
Why residual chlorine matters: Chlorine is the primary disinfectant in most drinking water systems. Maintaining residual chlorine above the minimum threshold throughout the distribution network is the critical barrier preventing microbial contamination between the treatment plant and the consumer. Too low — microbial risk. Too high — taste and by-product concerns.
The KNF-1005D uses a double platinum ring electrode with an ARM processor and noise-filtering algorithm — delivering stable, accurate readings at the low concentrations (0.05–0.3 mg/L) typical of distribution end-points where chlorine decay has reduced residuals to near-minimum levels.
| Specification |
Value |
| Measures |
Free chlorine, chlorine dioxide, ozone |
| Range |
0–5 mg/L default; up to 0–100 mg/L |
| Detection limit |
0.030 mg/L |
| Accuracy |
±3% |
| Response (T90) |
≤90 s |
| Design life |
>18 months |
| Output |
RS-485 + 4–20 mA |
4. KNF-102Pro — Conductivity / TDS Sensor
Why TDS / conductivity matters: TDS above 1,000 mg/L exceeds the GB5749 guideline value and indicates excessive dissolved minerals affecting taste, safety, and long-term health. Conductivity is the fastest and most cost-effective way to continuously track TDS — a sudden conductivity increase is an immediate signal of contamination or treatment process failure.
The KNF-102Pro simultaneously measures conductivity (0–600,000 μS/cm), TDS (0–9,999 ppm), salinity, and temperature from a single two-electrode graphite probe — with RS-485 digital output and IP68 protection.
| Specification |
Value |
| Conductivity range |
0–600,000 μS/cm |
| TDS range |
0–9,999 ppm |
| Accuracy |
<2.5% F.S. |
| Protection |
IP68, 6 bar / 50 m |
| Output |
RS-485 Modbus RTU |
5. KNF-400 — Complete Drinking Water Compliance Monitoring System
For locations requiring all four parameters monitored simultaneously — with on-site display, data logging, and cloud connectivity — Kainafu's KNF-400 tap water quality monitoring system integrates turbidity, residual chlorine, pH, temperature, TDS, and conductivity sensors in one cabinet.
Compliant with GB5749-2006, CJJ/T271-2017, and T/WSJD10-2020, the KNF-400 provides:
- 7-inch touch LCD display with real-time readings and alarm records
- 4G / GPRS cloud upload with configurable alarm thresholds
- WeChat push notifications when any parameter exceeds compliance limits
- Automatic data logging and USB export for regulatory reporting
- Built-in flowmeter and optional water leak detection
Quick Reference — Which Sensor for Which Compliance Check
| Compliance Parameter |
Standard Limit |
Kainafu Sensor |
| Turbidity |
≤1 NTU |
KNF-1004L |
| pH |
6.5–8.5 |
KNF-101PRO |
| Residual Chlorine |
≥0.05 mg/L |
KNF-1005D |
| TDS |
≤1,000 mg/L |
KNF-102Pro |
| All parameters combined |
Full compliance |
KNF-400 system |
About Kainafu: Shenzhen Kainafu Technology Co., Ltd. is an ISO 9001 and CMA-certified R&D manufacturer of water quality sensors based in Shenzhen, China — 50+ sensor types, all designed and built in-house, factory direct.
📧 Email: knfeco@knfsensors.com 🌐 Website: www.knfsensors.com
Shenzhen Kainafu Technology Co., Ltd. — Care for Environments and Health.
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