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Cost of Gas Adjustment Factor Rates and Information

The gas supply rate, or Cost of Gas Adjustment factor (GAF), and the Local Distribution Adjustment factor (LDAF) are semiannual rates charged by regulated Massachusetts gas companies.

Table of Contents

Gas Supply Rate/GAF Information

The Cost of Gas Adjustment Factor, or GAF, is the rate charged by regulated gas companies to recover the cost to purchase and transport gas supply to Massachusetts.  

The peak period (or winter) rate is in effect from November 1st through April 30th, and the off-peak period (or summer) rate is in effect from May 1st through October 31st.  

A gas company may, at any time, submit an amended GAF filing to the Department of Public Utilities (DPU). The amended GAF filing must be submitted 7 business days before the first billing cycle of the month in which it is proposed to take effect.  220 CMR 6.12. If an amended GAF is approved, we will post an update to this page and label the gas company's GAFs as REVISED.

LDAF Rate Information

The Local Distribution Adjustment Factor, or LDAF, is the rate charged by gas companies to recover distribution-related costs such as energy efficiency, environmental response, Attorney General consultants, residential assistance, and the gas system enhancement replacement program.

For company-specific delivery/distribution rate information, including Revenue Decoupling, please see the DPU's Delivery Rates and Tariffs page.

Historical GAF/LDAF rates and data

For GAF and LDAF rates in effect prior to the 2019 off-peak period, please download the GAF Historical Data Workbook.

Peak Period 2019-2020 Rates Revision 1 (Effective 12/1/19 through 4/30/20)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.4610 0.2669
Residential Heating R-3, R-4 $/Therm 0.5645 0.2669
G-40 $/Therm 0.5645 0.1684
G-41 $/Therm 0.5645 0.1227
G-42 $/Therm 0.5645 0.1116
G-43 $/Therm 0.5645 0.0987
G-50 $/Therm 0.4610 0.1684
G-51 $/Therm 0.4610 0.1227
G-52 $/Therm 0.4610 0.1116
G-53 $/Therm 0.4610 0.0987

Berkshire Gas CompanyREVISED

Rate Class Billing Unit GAF LDAF1
All Residential  $/Therm 0.6447 0.2495
G-41/G-51 $/Therm 0.6447 0.1235
G-42/G-52 $/Therm 0.6447 0.0990
G-43/G-53 $/Therm 0.6447 0.0782
T-54 $/Therm 0.6447 0.0254

1Berkshire's LDAF was also revised for effect December 1, 2019, in accordance with Section 1.8 of the Settlement Agreement with the Attorney General, approved in docket The Berkshire Gas Company, D.P.U. 18-40 (2019).

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Ccf 0.4372 0.1926
Residential Heating R-3, R-4 $/Ccf 0.4372 0.1704
G-1, School Rate $/Ccf 0.4372 0.0927

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.4917 0.4693
Residential Heating R-3, R-4 $/Therm 0.5093 0.4693
G-41 $/Therm 0.5093 0.3496
G-42 $/Therm 0.5093 0.2252
G-43 $/Therm 0.5093 0.1971
G-51 $/Therm 0.4917 0.3496
G-52 $/Therm 0.4917 0.2252
G-53 $/Therm 0.4917 0.1971

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.5700 0.3414
G-41, G-42, G-43 $/Therm 0.5700 0.1856
G-51, G-52, G-53 $/Therm 0.5700 0.1459

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6046 0.2183
G-41B/E, G-51B/E $/Therm 0.6046 0.1288
G-42B/E, G-52B/E $/Therm 0.6046 0.1257
G-43B/E, G-53B/E $/Therm 0.6046 0.1186
G-44B, G-54B $/Therm 0.3203 0.1136
G-44B, G-54B $/MDCQ 3.4442  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6031 0.2021
G-41, G-51 $/Therm 0.6031 0.1082
G-42, G-52 $/Therm 0.6031 0.1023
G-43, G-53 $/Therm 0.6031 0.0945

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6847 0.3089
G-41, G-51 $/Therm 0.6847 0.1909
G-42, G-52 $/Therm 0.6847 0.1476
G-43, G-53, T-1 $/Therm 0.6847 0.1366

Peak Period 2019-2020 Rates (Effective 11/1/19 through 11/30/19)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.4610 0.2669
Residential Heating R-3, R-4 $/Therm 0.5645 0.2669
G-40 $/Therm 0.5645 0.1684
G-41 $/Therm 0.5645 0.1227
G-42 $/Therm 0.5645 0.1116
G-43 $/Therm 0.5645 0.0987
G-50 $/Therm 0.4610 0.1684
G-51 $/Therm 0.4610 0.1227
G-52 $/Therm 0.4610 0.1116
G-53 $/Therm 0.4610 0.0987

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
All Residential  $/Therm 0.5901 0.2437
G-41/G-51 $/Therm 0.5901 0.1189
G-42/G-52 $/Therm 0.5901 0.0947
G-43/G-53 $/Therm 0.5901 0.0750
T-54 $/Therm 0.5901 0.0244

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Ccf 0.4372 0.1926
Residential Heating R-3, R-4 $/Ccf 0.4372 0.1704
G-1, School Rate $/Ccf 0.4372 0.0927

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.4917 0.4693
Residential Heating R-3, R-4 $/Therm 0.5093 0.4693
G-41 $/Therm 0.5093 0.3496
G-42 $/Therm 0.5093 0.2252
G-43 $/Therm 0.5093 0.1971
G-51 $/Therm 0.4917 0.3496
G-52 $/Therm 0.4917 0.2252
G-53 $/Therm 0.4917 0.1971

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.5700 0.3414
G-41, G-42, G-43 $/Therm 0.5700 0.1856
G-51, G-52, G-53 $/Therm 0.5700 0.1459

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6046 0.2183
G-41B/E, G-51B/E $/Therm 0.6046 0.1288
G-42B/E, G-52B/E $/Therm 0.6046 0.1257
G-43B/E, G-53B/E $/Therm 0.6046 0.1186
G-44B, G-54B $/Therm 0.3203 0.1136
G-44B, G-54B $/MDCQ 3.4442  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6031 0.2021
G-41, G-51 $/Therm 0.6031 0.1082
G-42, G-52 $/Therm 0.6031 0.1023
G-43, G-53 $/Therm 0.6031 0.0945

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.6847 0.3089
G-41, G-51 $/Therm 0.6847 0.1909
G-42, G-52 $/Therm 0.6847 0.1476
G-43, G-53, T-1 $/Therm 0.6847 0.1366

Off-Peak 2019 Rates Revision 3 (Effective 9/1/19 through 10/31/19)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.2941 0.2822
Residential Heating R-3, R-4 $/Therm 0.3260 0.2822
G-40 $/Therm 0.3260 0.1651
G-41 $/Therm 0.3260 0.1168
G-42 $/Therm 0.3260 0.1055
G-43 $/Therm 0.3260 0.0911
G-50 $/Therm 0.2941 0.1651
G-51 $/Therm 0.2941 0.1168
G-52 $/Therm 0.2941 0.1055
G-53 $/Therm 0.2941 0.0911

Berkshire Gas CompanyREVISED

Rate Class Billing Unit GAF LDAF
All Residential  $/Therm 0.2869 0.1767
G-41/G-51 $/Therm 0.2869 0.1027
G-42/G-52 $/Therm 0.2869 0.0823
G-43/G-53 $/Therm 0.2869 0.0654
T-54 $/Therm 0.2869 0.0210

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Ccf 0.4526 0.1619
Residential Heating R-3, R-4 $/Ccf 0.4526 0.1473
G-1, School Rate $/Ccf 0.4526 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.3050 0.4057
Residential Heating R-3, R-4 $/Therm 0.3241 0.4057
G-41 $/Therm 0.3241 0.3022
G-42 $/Therm 0.3241 0.1844
G-43 $/Therm 0.3241 0.1613
G-51 $/Therm 0.3050 0.3022
G-52 $/Therm 0.3050 0.1844
G-53 $/Therm 0.3050 0.1613

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.1139 0.3795
G-41, G-42, G-43 $/Therm 0.1139 0.2501
G-51, G-52, G-53 $/Therm 0.1139 0.1883

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3522 0.2702
G-41B/E, G-51B/E $/Therm 0.3522 0.1824
G-42B/E, G-52B/E $/Therm 0.3522 0.1773
G-43B/E, G-53B/E $/Therm 0.3522 0.1633
G-44B, G-54B $/Therm 0.2492 0.1533
G-44B, G-54B $/MDCQ 1.1696  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3525 0.2474
G-41, G-51 $/Therm 0.3525 0.1445
G-42, G-52 $/Therm 0.3525 0.1322
G-43, G-53 $/Therm 0.3525 0.1152

NSTAR Gas Company d/b/a Eversource EnergyREVISED

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.1661 0.2521
G-41, G-51 $/Therm 0.1661 0.1398
G-42, G-52 $/Therm 0.1661 0.1023
G-43, G-53, T-1 $/Therm 0.1661 0.0932

Off-Peak 2019 Rates Revision 2 (Effective 7/1/19 through 8/31/19)

Bay State Gas d/b/a Columbia Gas of MassachusettsREVISED

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.2941 0.2822
Residential Heating R-3, R-4 $/Therm 0.3260 0.2822
G-40 $/Therm 0.3260 0.1651
G-41 $/Therm 0.3260 0.1168
G-42 $/Therm 0.3260 0.1055
G-43 $/Therm 0.3260 0.0911
G-50 $/Therm 0.2941 0.1651
G-51 $/Therm 0.2941 0.1168
G-52 $/Therm 0.2941 0.1055
G-53 $/Therm 0.2941 0.0911

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
All Residential  $/Therm 0.4035 0.1767
G-41/G-51 $/Therm 0.4035 0.1027
G-42/G-52 $/Therm 0.4035 0.0823
G-43/G-53 $/Therm 0.4035 0.0654
T-54 $/Therm 0.4035 0.0210

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Ccf 0.4526 0.1619
Residential Heating R-3, R-4 $/Ccf 0.4526 0.1473
G-1, School Rate $/Ccf 0.4526 0.0868

Fitchburg Gas d/b/a UnitilREVISED

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.3050 0.4057
Residential Heating R-3, R-4 $/Therm 0.3241 0.4057
G-41 $/Therm 0.3241 0.3022
G-42 $/Therm 0.3241 0.1844
G-43 $/Therm 0.3241 0.1613
G-51 $/Therm 0.3050 0.3022
G-52 $/Therm 0.3050 0.1844
G-53 $/Therm 0.3050 0.1613

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.1139 0.3795
G-41, G-42, G-43 $/Therm 0.1139 0.2501
G-51, G-52, G-53 $/Therm 0.1139 0.1883

National Grid - Boston GasREVISED

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3522 0.2702
G-41B/E, G-51B/E $/Therm 0.3522 0.1824
G-42B/E, G-52B/E $/Therm 0.3522 0.1773
G-43B/E, G-53B/E $/Therm 0.3522 0.1633
G-44B, G-54B $/Therm 0.2492 0.1533
G-44B, G-54B $/MDCQ 1.1696  

National Grid - Colonial GasREVISED

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3525 0.2474
G-41, G-51 $/Therm 0.3525 0.1445
G-42, G-52 $/Therm 0.3525 0.1322
G-43, G-53 $/Therm 0.3525 0.1152

NSTAR Gas Company d/b/a Eversource EnergyREVISED

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.2338 0.2521
G-41, G-51 $/Therm 0.2338 0.1398
G-42, G-52 $/Therm 0.2338 0.1023
G-43, G-53, T-1 $/Therm 0.2338 0.0932

Off-Peak 2019 Rates Revision 1 (Effective 6/1/19 through 6/30/19)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.3736 0.2822
Residential Heating R-3, R-4 $/Therm 0.4055 0.2822
G-40 $/Therm 0.4055 0.1651
G-41 $/Therm 0.4055 0.1168
G-42 $/Therm 0.4055 0.1055
G-43 $/Therm 0.4055 0.0911
G-50 $/Therm 0.3736 0.1651
G-51 $/Therm 0.3736 0.1168
G-52 $/Therm 0.3736 0.1055
G-53 $/Therm 0.3736 0.0911

Berkshire Gas CompanyREVISED

Rate Class Billing Unit GAF LDAF
All Residential  $/Therm 0.4035 0.1767
G-41/G-51 $/Therm 0.4035 0.1027
G-42/G-52 $/Therm 0.4035 0.0823
G-43/G-53 $/Therm 0.4035 0.0654
T-54 $/Therm 0.4035 0.0210

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Ccf 0.4526 0.1619
Residential Heating R-3, R-4 $/Ccf 0.4526 0.1473
G-1, School Rate $/Ccf 0.4526 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.3968 0.4057
Residential Heating R-3, R-4 $/Therm 0.4159 0.4057
G-41 $/Therm 0.4159 0.3022
G-42 $/Therm 0.4159 0.1844
G-43 $/Therm 0.4159 0.1613
G-51 $/Therm 0.3968 0.3022
G-52 $/Therm 0.3968 0.1844
G-53 $/Therm 0.3968 0.1613

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.1139 0.3795
G-41, G-42, G-43 $/Therm 0.1139 0.2501
G-51, G-52, G-53 $/Therm 0.1139 0.1883

National Grid - Boston GasREVISED

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3977 0.2702
G-41B/E, G-51B/E $/Therm 0.3977 0.1824
G-42B/E, G-52B/E $/Therm 0.3977 0.1773
G-43B/E, G-53B/E $/Therm 0.3977 0.1633
G-44B, G-54B $/Therm 0.2948 0.1533
G-44B, G-54B $/MDCQ 1.1680  

National Grid - Colonial GasREVISED

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3980 0.2474
G-41, G-51 $/Therm 0.3980 0.1445
G-42, G-52 $/Therm 0.3980 0.1322
G-43, G-53 $/Therm 0.3980 0.1152

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3344 0.2521
G-41, G-51 $/Therm 0.3344 0.1398
G-42, G-52 $/Therm 0.3344 0.1023
G-43, G-53, T-1 $/Therm 0.3344 0.0932

Off-Peak 2019 Rates (Effective 5/1/19 through 5/31/19)

Bay State Gas d/b/a Columbia Gas of Massachusetts

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.3736 0.2822
Residential Heating R-3, R-4 $/Therm 0.4055 0.2822
G-40 $/Therm 0.4055 0.1651
G-41 $/Therm 0.4055 0.1168
G-42 $/Therm 0.4055 0.1055
G-43 $/Therm 0.4055 0.0911
G-50 $/Therm 0.3736 0.1651
G-51 $/Therm 0.3736 0.1168
G-52 $/Therm 0.3736 0.1055
G-53 $/Therm 0.3736 0.0911

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
All Residential  $/Therm 0.4605 0.1767
G-41/G-51 $/Therm 0.4605 0.1027
G-42/G-52 $/Therm 0.4605 0.0823
G-43/G-53 $/Therm 0.4605 0.0654
T-54 $/Therm 0.4605 0.0210

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Ccf 0.4526 0.1619
Residential Heating R-3, R-4 $/Ccf 0.4526 0.1473
G-1, School Rate $/Ccf 0.4526 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
Residential Non-Heating R-1, R-2 $/Therm 0.3968 0.4057
Residential Heating R-3, R-4 $/Therm 0.4159 0.4057
G-41 $/Therm 0.4159 0.3022
G-42 $/Therm 0.4159 0.1844
G-43 $/Therm 0.4159 0.1613
G-51 $/Therm 0.3968 0.3022
G-52 $/Therm 0.3968 0.1844
G-53 $/Therm 0.3968 0.1613

Liberty Utilities

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.1139 0.3795
G-41, G-42, G-43 $/Therm 0.1139 0.2501
G-51, G-52, G-53 $/Therm 0.1139 0.1883

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.4471 0.2702
G-41B/E, G-51B/E $/Therm 0.4471 0.1824
G-42B/E, G-52B/E $/Therm 0.4471 0.1773
G-43B/E, G-53B/E $/Therm 0.4471 0.1633
G-44B, G-54B $/Therm 0.3423 0.1533
G-44B, G-54B $/MDCQ 1.1897  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.4474 0.2474
G-41, G-51 $/Therm 0.4474 0.1445
G-42, G-52 $/Therm 0.4474 0.1322
G-43, G-53 $/Therm 0.4474 0.1152

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
All Residential $/Therm 0.3344 0.2521
G-41, G-51 $/Therm 0.3344 0.1398
G-42, G-52 $/Therm 0.3344 0.1023
G-43, G-53, T-1 $/Therm 0.3344 0.0932

 

Contact

Phone

Open M-F 9am- 5pm

Online

For questions related to your gas bill, visit the DPU Consumer Division page 
For non-billing gas inquiries Non-BillingGas.Inquiries@mass.gov

Address

Department of Public Utilities
One South Station
5th Floor
Boston, MA 02110
Last updated: November 27, 2019
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