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Residential Sewer Charges Explained

Every year in May, we recalculate your residential sewer charge based on the average of your billed water usage during December, January, and February for the previous five-year period. For the next 12 months your sewer charges will be this new average or your actual water consumption, whichever is lower.

As a residential customer, am I billed sewer on all my water consumption?
Yes, your sewer charge is based on the average of your billed water usage during December, January, and February for the previous five-year period.

How is my sewer volume determined?
In most instances it is impractical to measure the volume of domestic sewage discharged into the sanitary sewer system for the purpose of billing. Therefore, the volume of domestic sewage is billed based on the amount of water measured at the meter.

Not all my water goes down the sewer, am I still charged for sewer for this water?
Each single-family residential property is assigned a limit referred to as the Sewer Cap (or cap). The cap is sometimes referred to as the Winter Quarter Average. This cap will limit the billing for sewer. At any point your water consumption usage exceeds your cap, only the cap usage amount will be billed. Below is a chart with examples of how this cap works:

Water Consumption Account Cap  Sewer Volume Billed
2 5 2
5 5 5
8 5 5
*billed amounts are in 1,000’s of gallons

How is my account’s Cap Calculated?
Your water consumption with the City of Tulsa for the past 5 years (if available) is used to determine your Cap. Each spring, your average water consumption billed in December, January, and February for the previous five years is calculated (15 total months of consumption). The new cap is then used for your May billing until the following spring when your next Cap is calculated.

What if I am a new customer?
New customers will use the property’s current cap until the following spring until a new cap can be calculated. If the property does not have a Cap, the citywide average of 5 is used. Once a customer has at least 3 calculation months (December, January, and February billing months) the city will use these months to recalculate the cap in the spring.

How do I know what my new cap will be each year?
Your new cap starts with your May bill. If your cap is increase by more than 4, a letter will be mailed to your billing address to inform you of your new cap.

What if I had an event such as a leak during the months used to calculate my cap?
Because the cap is calculated using a total of 15 months, minor leaks or spikes in consumption do not tend to affect your cap. City of Tulsa staff reviews large increases in the cap and look for consumption anomalies to exclude those months in the calculation. In the event that you believe your cap is mis-calculated, or if you have information that may not be noted on your account such as repairs for large leaks, you can contact Customer Care at 311 and a representative can determine if that month was already excluded and if removing that month will change your cap .

What if the City of Tulsa estimated my bill during the calculation months?
If an estimate was used during a month used for the calculation and the next non-estimated month was not used in your cap calculation, the estimated month is removed from the calculation formula. 

Can I request my cap be adjusted?
You may contact a customer care representative at 311 and request a cap review. There are a few general pieces of information you will want to have available:

If my cap is adjusted, will I receive a credit?
Based on your situation, you may be eligible to receive a credit on your account for the difference of what was billed on the previously calculated cap verses the adjusted cap. The adjustment will be calculated back to the first month the last calculated cap became effective (i.e. the May bill.)

What if I water my lawn or keep my pool running all winter long?
If you find the cap policy still does not accurately reflect the sewer discharge at your residence, you have the option to apply for a permit to install a separate dedicated water line at your property. If the water line is not connected to the sewer lines, then only water will be billed for the consumption measured on this separate line. The separate line will be subject to the current monthly meter service charge as outlined in the City of Tulsa ordinance.