How to choose a water quality meter
By Grant, Inspection Tool Specialists. Reviewed November 2026.
Three questions decide which water quality meter you need: which parameters matter for your water, whether you need spot checks or continuous monitoring, and which results must be backed by a laboratory. Answer those first. A meter gives an on-site reading; it does not replace laboratory testing for microbiology.
This guide covers portable, pocket and benchtop meters, chlorine and turbidity instruments, and online transmitters for water and other liquids.
What are you measuring?
| Parameter | What it tells you | Instrument |
|---|---|---|
| pH | Acidity or alkalinity; affects treatment, corrosion and process chemistry | pH meter |
| Conductivity, TDS and salinity | Total dissolved salts; TDS is derived from conductivity | Conductivity or TDS meter |
| Dissolved oxygen | Oxygen available to aquatic life, aeration and wastewater treatment | Dissolved oxygen meter |
| Turbidity | Clarity; high turbidity affects filters and disinfection | Turbidity meter |
| Free and total chlorine | Disinfectant residual in treated water | Chlorine meter with reagent |
| Hardness, colour and other chemistry | Specific chemical tests | Photometer with test reagents |
Spot checks or continuous monitoring?
Pocket and portable meters suit spot checks at the tap, tank or process point. Benchtop meters suit a laboratory or a control room. Online transmitters measure continuously and send readings to a controller or logger, which is the choice when a reading must be watched through the day. An online system needs installation, power and maintenance, so its cost is well above a handheld meter.
Calibration and electrodes
pH and dissolved-oxygen readings drift. Calibrate them as the manufacturer directs, using pH buffer solutions or the calibration steps in the manual, and keep the record. Electrodes age and need replacing, so ask about replacement electrodes when you buy. Chlorine readings depend on the reagent: DPD-1 strips measure free chlorine and DPD-4 strips measure total chlorine. Check that the reagent is in date and read it within the time the method allows.
Borehole and municipal water are different
A borehole that has not been tested has no baseline to compare against. For a borehole supply, the usual sequence is to start with a comprehensive assessment by an accredited laboratory, which sets the parameters, the testing frequency and the action limits. Meters then support daily operational checks, such as pH, conductivity or turbidity, and residual chlorine where chlorination is used. The meters do not establish microbiological safety, so laboratory verification stays in the plan.
Which meter should I buy?
| Application | Suggested starting point |
|---|---|
| Routine pH, conductivity and TDS, portable | PCT-407 portable pH, conductivity and TDS meter |
| Waterproof pocket checks: pH, conductivity and dissolved oxygen | 7000 Series pocket meters |
| Waterproof multiparameter: pH, conductivity, TDS and salinity | 8200 Series meter |
| Turbidity, with four-point calibration | TUB-430F turbidity meter |
| Free and total chlorine | FTC-420 chlorine meter (DPD-4 strips for total chlorine are available separately) |
| Dissolved oxygen, portable | PDO-408 dissolved oxygen meter |
| Benchtop laboratory or control room | PL-700 benchtop series |
| Continuous online monitoring | PCW-3000A online transmitter |
As a guide to our current range, including VAT: basic pH meters from about R1,800; pocket and portable multiparameter meters from about R1,700 to R8,000; turbidity meters from about R7,900 to R15,400; chlorine meters from about R5,400; online transmitters from about R8,400. Prices change, so check the product pages and confirm the accessories you need.
What affects the reading?
- Sample condition: oily, cloudy or scaling water can coat electrodes. Rinse between samples and clean the electrode as the manual directs.
- Temperature: pH and conductivity readings change with temperature. Use a meter with automatic temperature compensation where you read across a range of temperatures.
- Range: calibrate near the values you expect to measure.
- Accessories: check that the buffers, standards, electrodes, sample bottles and carry case you need are in the quote.
Which limits apply?
The limits you must meet come from your food safety plan, your water authority or the regulation that applies to you, not from the meter. Confirm those before you choose the parameters and the action levels.
Questions we will ask you
Tell us the water source (borehole, municipal, process, wastewater or other), the parameters you need, the expected range, whether you need spot checks or continuous monitoring, any treatment in place such as filtration, UV, chlorination or reverse osmosis, whether the water is stored, how the water is used, and whether a laboratory baseline has been done. With that we can recommend a meter and provide pricing.