PTV 1000 in a room overlooking a treated water facility

Treated water turbidity monitoring

Track changes in turbidity at a final-water, storage or transfer point within a drinking-water system.

Define the water that reaches the sample point

A final-water outlet, reservoir outlet and transfer main may all see different water during the day. Walk through the paths that pumps and valves can create, then document which path supplies the sample at each operating state.

Check that the analyser still receives a representative sample during low demand and after a pump change. Consider the time taken for water to travel to the analyser so a change in the trend can be matched to the right event.

PTV 1000 overlooking a treated-water facility

Put the transfer event on the same timeline

The example shows a brief change following a transfer event. Check pump and valve records, then allow for the time between the sample point and the analyser.

Illustrative readings in FNU. This example is provided for interpretation practice.

Transfer pump starts at minute 4

View example readings

Illustrative data
Minute	Turbidity (FNU)
0	0.050
2	0.049
4	0.050
6	0.051
8	0.078
10	0.073
12	0.052
14	0.048
16	0.050
18	0.049

Make changes in the trend traceable

Put pump starts, valve changes and maintenance events on the same timeline as the turbidity readings. If the line has been isolated, record when the sample resumed and when it became representative again.

For a comparison sample, choose a point that represents the same water and record the time and optical method. Comparing like-for-like samples is particularly useful when reviewing changes across storage turnover or transfer periods.