Measuring pH of storm water onsite

HANNA - STORM WATER PHUrban and construction site areas tend to have large amounts of impervious surfaces, resulting in large volumes of runoff. As storm water flows over these impervious surfaces, chemicals, pollutants, debris, and sediment are gathered. This pollutant and nutrient-rich storm water ultimately drains into sewers, where it continues to a wastewater plant for treatment or into a natural water body such as rivers, lakes, wetlands, and estuaries.

Most local authorities dictate that storm water leaving a construction site must be within a pH range of 6.5 to 8.5.

The pH of storm water is typically measured at the point of discharge to the waterway or at the point that it leaves the construction site. Measurement can be performed either directly in the flow or storm water or in a sample that has been collected in a bottle.  When a pH reading is outside this range, treatment is required. Additionally, the onsite source of pollution must be identified and remedied. At construction sites, pollutants can come from a variety of sources.

Best management practices (BMPs) such as silt fences, retention ponds, and hay bales are often utilised to catch and filter storm water runoff, but damaged silt fences or high sediment build up reduce the efficiency of BMPs.

Hanna Instruments’ support team recommends the HI98190 Waterproof Portable pH/ORP meter for the measurement of the pH of storm water onsite.


  • Waterproof and rugged
  • Accurate with data logging

The HI98190 is a convenient and valuable solution for pH measurement needs.

Hanna Instruments

JHB: (011) 615 6076
CT: (021) 946 1722
DBN (031) 701 2711
[email protected]


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