From the BJWSA Facebook page:
Customers with even-numbered addresses are asked to irrigate on Wednesdays, Fridays and Sundays from midnight to 2 am or from 9 am to noon. Those with odd-numbered addresses are asked to irrigate on Tuesdays, Thursdays and Saturdays. Mondays are reserved as “no irrigation days” to accommodate for the very high water demands that are typically experienced specifically on Mondays.
The guidelines were developed in cooperation with Clemson Extension Service in order to ensure that lawns are being watered at appropriate times for health and growth.