We want to explain a brief dip in the City’s chlorine level back in February 2026. In short, it was very small, it was quickly restored, and there is no health concern.
What happened
On February 19, 2026, the chlorine level in water leaving the treatment plant tested at 0.19 mg/L. The state minimum is 0.2 mg/L, so the reading was just 0.01 mg/L below it. The next reading, on February 20, was 0.24 mg/L, comfortably above the minimum.
The chlorine feed was turned up when the low reading was seen. The level was very likely back above the minimum well within the four hours ADEQ allows. But only one reading was recorded that day, so there was no record to show it, and the day was counted as a violation.
Why the notice is going out now
Tierra Water Management was the City’s operator of record through June 30, 2026. The City has operated its own system since July 1, 2026. Before the handover, we confirmed that ADEQ showed no open violations for the City, and no violation was ever issued to us for February.
ADEQ raised the matter in early November 2026 and asked that a public notice be distributed. The City has posted it at its official posting locations, and a notice will be distributed with the November 2026 utility bill.
Is there a health concern?
No. This was not an emergency, and you don’t need to boil your water or take any other action. The chlorine level dipped very slightly for a short time and was restored.
What’s been done
Follow-up testing has been reviewed with the operator. If a reading ever comes in below 0.2 mg/L, the chlorine is increased and the level is retested to confirm it’s back above the minimum within four hours.
Questions
If you have questions, please contact City of Tombstone Public Works at (520) 457-3415, or me directly at (520) 448‑4975 ext. 107.
Sincerely,
Paul Juhl
Tierra Water Management