32 Ill. Adm. Code 346.630
Pool Water Purity
Section 346.630 Pool Water Purity
a) Pool
water purification system shall be run sufficiently to maintain the
conductivity of the pool water below 20 microsiemens per centimeter under
normal circumstances. If pool water conductivity rises above 20 microsiemens
per centimeter, the licensee shall take prompt actions to lower the pool water
conductivity and shall take corrective actions to prevent future recurrences.
b) The
licensee shall measure the pool water conductivity frequently enough, but no
less than weekly, to assure that the conductivity remains below 20 microsiemens
per centimeter. Conductivity meters shall be calibrated at least annually.