If you see a credit on your electric, gas or water bill beginning in July, it's not a mistake.

That's right, you could end up getting some money back on your upcoming bills. However, how much you will receive is unclear.

This week, the Pennsylvania Public Utility Commission issued an order requiring a "negative surcharge" or monthly credit on customer bills for 17 electric, natural gas, and water and wastewater utilities. The order was approved by a 5-0 vote and is subject to appeal.

The refunds to customers combined are around $324 million and are the result of the decrease in federal corporate tax rates and other tax changes under the Tax Cuts and Jobs Act of 2017.

Since the companies' current rates were approved prior to the passing of the Tax Cuts and Jobs Act, the PUC says it is passing on those savings to consumers.

"As economic regulators, it is the commission's responsibility to ensure that utility rates are just and reasonable. Further, it is necessary for utility rates to reflect relevant tax expenses," Chairman Gladys M Brown said in a statement at the PUC's meeting on Thursday.

The PUC says this order follows an extensive investigation into the effects of federal tax reform on the rates charged by Commission-regulated utilities - which, among other things, reflect annual taxes owed both to the federal and state governments.

Utility bills are broken down into two charges and Nils Hagen-Frederiksen, press secretary for the PUC, noted that consumers will see the decrease from the distribution charges.

How much consumers will see varies based on usage as well as the company's current rates. The charges will decrease from .56 percent to 8.55 percent depending on the company. Consumers will continue to see the credit on their bill until the company comes back to the PUC to ask for a change in rates which in some cases could be multiple years, according to Hagen-Frederiksen.

The 17 public utilities required to provide this credit to consumers include the following:

PPL Electric Utilities Corporation,

Metropolitan Edison Company,

UGI Central Penn Gas Inc.,

UGI Penn Natural Gas Inc.,

UGI Utilities, Inc., Gas Division,

Pennsylvania-American Water Company

Pennsylvania-American Water Company - Wastewater,

Citizens' Electric Company of Lewisburg,

Pennsylvania Electric Company,

Pennsylvania Power Company,

Pike County Light & Power Company,

Wellsboro Electric Company,

West Penn Power Company,

PECO Energy Company (Gas Division),

National Fuel Gas Distribution Corporation,

Peoples Gas Company LLC,

Peoples Natural Gas Company LLC - Equitable Division

The monthly credits begin on July 1. It's not exactly clear at this point how much customers will receive.

Here is the percentage the charges will decrease for some companies as ordered by the PUC:

Metropolitan Edison Co. -8.55

PPL Electric Utilities Corp. -0.56

UGI Utilities Inc. - Electric -1.04

UGI Utilities Inc. - Gas Division -5.78

Pennsylvania American Water Co. -6.79

Suez Water Pennsylvania Inc. -3.72

York Water Company -2.05

Spokespeople for Metropolitan Edison Company and UGI Utilities said the companies are reviewing the orders. PPL Electric Utilities Corporation said in a statement that it is reviewing the order and noted that this is a complex issue. Pennsylvania American Water said in a statement that it is reviewing the order and that the process of how the negative surcharge will be applied to customers' bills and how much is to be determined.

The PUC has held off this requirement for seven companies whose rates are currently in front of the PUC or are expected to file by Aug. 1. In those situations, the PUC has asked the companies to address the impact of any tax savings as part of the overall rate design for each utility. Those companies include UGI Utilities Inc. (Electric), Columbia Gas of Pennsylvania Inc., Duquesne Light Company, PECO Energy Company (Electric), York Water Company, Suez Water Pennsylvania Inc. and Aqua Pennsylvania Inc.

Columbia Water Company was directed to file a tariff or tariff supplement within 10 days, replacing their current rates, which were declared to be "temporary" by the PUC in March 2018. The rates for Peoples Natural Gas Company LLC and Newtown Artesian Water Company will continue.