Prorate a Chicago Water Bill.  First, get a copy of the most recent water bill.  Find out the billing cycle.  For a non-metered account it is issued every six months so look at the bill and use the month it is issued and then add six months for the other billing month.  Determine the last date through which the water bill has been paid or is supposed to be paid.  By the way on a non-metered bill, water and sewer are billed together and are typically each 1/2 of the total bill amount.  Then do the following calculations:

Closing Date – Last day of previous water/sewer billing period = Number of Days to charge per diem water/sewer charge

Last water/sewer bill total amount/180 – per diem rate

Prorated Amount that you should be credited at closing = Number of Days  X (times) Per Diem Rate

Example:

• Closing Date is July 31, 2015
• Last day of last water/sewer billing cycle:  April 30, 2015
• Last total bill:  $379.14
• 7/31/2015 – 4/30/2015 = 92 days
• 379.14/180 = $2.11
• 92 days x $2.11/day = $194.12

The amount the seller should pay the buyer at closing is $194.12

Conclusion:

Water Bills and Sewer Bills are traditionally not prorated in the Chicago, Cook County and Collar County areas.  But they could be prorated if needed and/or desired by clients.  In Chicago, the Chicago Water Certification is really the only thing traditionally required at closing to ensure that there is no lien from a prior unpaid water bill.  However, since the water bill issue date controls who is liable on that day by who is the owner on the day the bill is issued instead of who was the owner during period in which the bill accrues.