Independent record · not an official water authority publication
Cold Main Water Notes
What comes out of the tap here — one street, sampled monthly
1Latest Readings
Sample taken kitchen cold tap, first draw, 08:40, this month
| Parameter | Reading | Guide range | Status |
|---|
| pH | 7.4 | 6.5–9.5 | Normal |
| Total hardness (mg/L CaCO₃) | 218 | — | Hard |
| Free chlorine (mg/L) | 0.31 | 0.1–0.5 | Normal |
| Turbidity (NTU) | 0.18 | <1.0 | Normal |
| Lead (µg/L) | 2.1 | <10 | Normal |
| Nitrate (mg/L) | 11.4 | <50 | Normal |
| Iron (µg/L) | 64 | <200 | Normal, watching trend |
| Conductivity (µS/cm) | 612 | — | Normal for area |
2What Each Figure Means
- pH measures acidity/alkalinity on a 0–14 scale. Mains water in this area runs slightly alkaline due to the chalk aquifer it's drawn from; anything 6.5–9.5 is unremarkable.
- Hardness reflects dissolved calcium and magnesium. 218 mg/L sits in the "hard" band — expect scale in kettles, no health relevance.
- Free chlorine is residual disinfectant. Too little and the network risk of recontamination rises; too much tastes of it. 0.31 is comfortably mid-range.
- Turbidity is cloudiness from suspended particles, tested because a rising trend often precedes a mains disturbance before anything else shows up.
- Lead is tested at first draw specifically because overnight standing water in old service pipes is when lead pickup is highest. This street still has some pre-1970 lead supply pipe on the property side.
- Iron above 100µg/L can start to taste metallic or stain white porcelain; 64 is below that but has crept up from 40 two months ago, worth another reading before calling it a trend.
Notice
This is an independent household record, not a statutory compliance test and not affiliated with any water authority. Method and limitations are described in clause 3. Treat single readings as indicative, not as a certified analysis.
3How Samples Are Taken
- Point
- Kitchen cold tap, unfiltered, no aerator removed.
- Draw
- First draw after minimum 6hr standing (overnight).
- Frequency
- Monthly, same week each month where possible.
- Kit
- Home test strips for chlorine/pH/hardness; metals sent to a mail-in lab kit quarterly, monthly figures interpolated between lab results for iron and lead.
- Caveat
- Strip readings have wider error margins than lab results, roughly ±10–15%.
4The Month The Readings Went Odd
In the March record, free chlorine spiked to 0.9 mg/L for two consecutive samples and turbidity briefly read 1.4 NTU, both outside the normal range recorded here in three years of readings. No official notice was issued for the street. The most likely explanation, based on the timing, is main-flushing work that was underway on the adjoining road that week — flushing routinely raises both chlorine and turbidity temporarily as sediment is stirred and dosing is increased to compensate. Readings returned to baseline within nine days and have stayed there since. Recorded here in case it is useful to anyone else on the street who noticed a smell that month and wondered.