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Cost of Gas Adjustment Factor Rates and Information

Cost of Gas Adjustment (GAF) and Local Distribution Adjustment (LDAF) are semiannual rates charged by regulated Massachusetts gas companies

Table of Contents

Explanation of Rates

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.

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 Rates and Tariffs page.

Currently in Effect: Peak Period 2018-2019 (Effective 11/1/18)

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

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.5694 0.2660
R-3, R-4 $/Therm 0.6482 0.2660
G-40 $/Therm 0.6482 0.1478
G-41 $/Therm 0.6482 0.1069
G-42 $/Therm 0.6482 0.0974
G-43 $/Therm 0.6482 0.0822
G-50 $/Therm 0.5694 0.1478
G-51 $/Therm 0.5694 0.1069
G-52 $/Therm 0.5694 0.0974
G-53 $/Therm 0.5694 0.0822


Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.5559 0.1610
R-3, R-4 $/Therm 0.6769 0.1610
G-41 $/Therm 0.6769 0.1039
G-42 $/Therm 0.6769 0.0767
G-43 $/Therm 0.6769 0.0576
G-51 $/Therm 0.5559 0.1039
G-52 $/Therm 0.5559 0.0767
G-53 $/Therm 0.5559 0.0576
T-54 $/Therm 0.5559 0.0164

 

Blackstone Gas Company

 

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.7550 0.1619
R-3, R-4 $/Ccf 0.7550 0.1473
G-1, School Rate $/Ccf 0.7550 0.0868

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.4453 0.3897
R-3, R-4 $/Therm 0.5512 0.3897
G-41 $/Therm 0.5512 0.2883
G-42 $/Therm 0.5512 0.1724
G-43 $/Therm 0.5512 0.1526
G-51 $/Therm 0.4453 0.2883
G-52 $/Therm 0.4453 0.1724
G-53 $/Therm 0.4453 0.1526

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3642 0.3136
G-41, G-42, G-43 $/Therm 0.3642 0.2193
G-51, G-52, G-53 $/Therm 0.3642 0.1624

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6025 0.3138
G-41B/E, G-51B/E $/Therm 0.6025 0.2181
G-42B/E, G-52B/E $/Therm 0.6025 0.2068
G-43B/E, G-53B/E $/Therm 0.6025 0.1898
G-44B, G-54B $/Therm 0.2844 0.1751
G-44B, G-54B $/MDCQ 3.6952  

 

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.6026 0.2689
G-41, G-51 $/Therm 0.6026 0.1608
G-42, G-52 $/Therm 0.6026 0.1396
G-43, G-53 $/Therm 0.6026 0.1135

 

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.5782 0.2406
G-41, G-51 $/Therm 0.5782 0.1288
G-42, G-52 $/Therm 0.5782 0.0927
G-43, G-53, T-1 $/Therm 0.5782 0.0844

In effect until 10/31/18: Off-Peak 2018 Revision 2 (Effective 7/1/18)

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

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2410 0.2392
R-3, R-4 $/Therm 0.3320 0.2392
G-40 $/Therm 0.3320 0.1384
G-41 $/Therm 0.3320 0.0974
G-42 $/Therm 0.3320 0.0880
G-43 $/Therm 0.3320 0.0711
G-50 $/Therm 0.2410 0.1384
G-51 $/Therm 0.2410 0.0974
G-52 $/Therm 0.2410 0.0880
G-53 $/Therm 0.2410 0.0711

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2110 0.1940
R-3, R-4 $/Therm 0.1930 0.1940
G-41 $/Therm 0.1930 0.1030
G-42 $/Therm 0.1930 0.0750
G-43 $/Therm 0.1930 0.0570
G-51 $/Therm 0.2110 0.1030
G-52 $/Therm 0.2110 0.0750
G-53 $/Therm 0.2110 0.0570
T-54 $/Therm 0.2110 0.0140

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.4403 0.1417
R-3, R-4 $/Ccf 0.4403 0.1368
G-1, School Rate $/Ccf 0.4403 0.0668

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3336 0.3302
R-3, R-4 $/Therm 0.3345 0.3302
G-41 $/Therm 0.3345 0.2196
G-42 $/Therm 0.3345 0.1241
G-43 $/Therm 0.3345 0.1115
G-51 $/Therm 0.3336 0.2196
G-52 $/Therm 0.3336 0.1241
G-53 $/Therm 0.3336 0.1115

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3116 0.3091
G-41, G-42, G-43 $/Therm 0.3116 0.2090
G-51, G-52, G-53 $/Therm 0.3116 0.1517

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3547 0.3615
G-41B/E, G-51B/E $/Therm 0.3547 0.2150
G-42B/E, G-52B/E $/Therm 0.3547 0.1864
G-43B/E, G-53B/E $/Therm 0.3547 0.1685
G-44B, G-54B $/Therm 0.2472 0.1472
G-44B, G-54B $/MDCQ 1.1417  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3529 0.3173
G-41, G-51 $/Therm 0.3529 0.1566
G-42, G-52 $/Therm 0.3529 0.1207
G-43, G-53 $/Therm 0.3529 0.0793

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.2762 0.2412
G-41, G-51 $/Therm 0.2762 0.1473
G-42, G-52 $/Therm 0.2762 0.1085
G-43, G-53, T-1 $/Therm 0.2762 0.1001

Off-Peak 2018 Revision 1 (Effective 6/1/18)

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

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2782 0.2381
R-3, R-4 $/Therm 0.3692 0.2381
G-40 $/Therm 0.3692 0.1373
G-41 $/Therm 0.3692 0.0966
G-42 $/Therm 0.3692 0.0873
G-43 $/Therm 0.3692 0.0707
G-50 $/Therm 0.2782 0.1373
G-51 $/Therm 0.2782 0.0966
G-52 $/Therm 0.2782 0.0873
G-53 $/Therm 0.2782 0.0707

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3460 0.1940
R-3, R-4 $/Therm 0.3160 0.1940
G-41 $/Therm 0.3160 0.1030
G-42 $/Therm 0.3160 0.0750
G-43 $/Therm 0.3160 0.0570
G-51 $/Therm 0.3460 0.1030
G-52 $/Therm 0.3460 0.0750
G-53 $/Therm 0.3460 0.0570
T-54 $/Therm 0.3460 0.0140

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.4403 0.1417
R-3, R-4 $/Ccf 0.4403 0.1368
G-1, School Rate $/Ccf 0.4403 0.0668

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3336 0.3302
R-3, R-4 $/Therm 0.3345 0.3302
G-41 $/Therm 0.3345 0.2196
G-42 $/Therm 0.3345 0.1241
G-43 $/Therm 0.3345 0.1115
G-51 $/Therm 0.3336 0.2196
G-52 $/Therm 0.3336 0.1241
G-53 $/Therm 0.3336 0.1115

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3116 0.3091
G-41, G-42, G-43 $/Therm 0.3116 0.2090
G-51, G-52, G-53 $/Therm 0.3116 0.1517

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3547 0.3615
G-41B/E, G-51B/E $/Therm 0.3547 0.2150
G-42B/E, G-52B/E $/Therm 0.3547 0.1864
G-43B/E, G-53B/E $/Therm 0.3547 0.1685
G-44B, G-54B $/Therm 0.2472 0.1472
G-44B, G-54B $/MDCQ 1.1417  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3529 0.3173
G-41, G-51 $/Therm 0.3529 0.1566
G-42, G-52 $/Therm 0.3529 0.1207
G-43, G-53 $/Therm 0.3529 0.0793

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.2762 0.2412
G-41, G-51 $/Therm 0.2762 0.1473
G-42, G-52 $/Therm 0.2762 0.1085
G-43, G-53, T-1 $/Therm 0.2762 0.1001

Off-Peak 2018 (Effective 5/1/18)

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

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.2782 0.2381
R-3, R-4 $/Therm 0.3692 0.2381
G-40 $/Therm 0.3692 0.1373
G-41 $/Therm 0.3692 0.0966
G-42 $/Therm 0.3692 0.0873
G-43 $/Therm 0.3692 0.0707
G-50 $/Therm 0.2782 0.1373
G-51 $/Therm 0.2782 0.0966
G-52 $/Therm 0.2782 0.0873
G-53 $/Therm 0.2782 0.0707

Berkshire Gas Company

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3460 0.1940
R-3, R-4 $/Therm 0.3160 0.1940
G-41 $/Therm 0.3160 0.1030
G-42 $/Therm 0.3160 0.0750
G-43 $/Therm 0.3160 0.0570
G-51 $/Therm 0.3460 0.1030
G-52 $/Therm 0.3460 0.0750
G-53 $/Therm 0.3460 0.0570
T-54 $/Therm 0.3460 0.0140

Blackstone Gas Company

Rate Class Billing Unit GAF LDAF
R-1. R-2 $/Ccf 0.4403 0.1417
R-3, R-4 $/Ccf 0.4403 0.1368
G-1, School Rate $/Ccf 0.4403 0.0668

Fitchburg Gas d/b/a Unitil

Rate Class Billing Unit GAF LDAF
R-1, R-2 $/Therm 0.3336 0.3302
R-3, R-4 $/Therm 0.3345 0.3302
G-41 $/Therm 0.3345 0.2196
G-42 $/Therm 0.3345 0.1241
G-43 $/Therm 0.3345 0.1115
G-51 $/Therm 0.3336 0.2196
G-52 $/Therm 0.3336 0.1241
G-53 $/Therm 0.3336 0.1115

Liberty Utilities

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3116 0.3091
G-41, G-42, G-43 $/Therm 0.3116 0.2090
G-51, G-52, G-53 $/Therm 0.3116 0.1517

National Grid - Boston Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3547 0.3615
G-41B/E, G-51B/E $/Therm 0.3547 0.2150
G-42B/E, G-52B/E $/Therm 0.3547 0.1864
G-43B/E, G-53B/E $/Therm 0.3547 0.1685
G-44B, G-54B $/Therm 0.2472 0.1472
G-44B, G-54B $/MDCQ 1.1417  

National Grid - Colonial Gas

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.3529 0.3173
G-41, G-51 $/Therm 0.3529 0.1566
G-42, G-52 $/Therm 0.3529 0.1207
G-43, G-53 $/Therm 0.3529 0.0793

NSTAR Gas Company d/b/a Eversource Energy

Rate Class Billing Unit GAF LDAF
Residential $/Therm 0.2541 0.2412
G-41, G-51 $/Therm 0.2541 0.1473
G-42, G-52 $/Therm 0.2541 0.1085
G-43, G-53, T-1 $/Therm 0.2541 0.1001

Historical GAF/LDAF rates and data

For GAF and LDAF rates in effect prior to the 2018/19 peak period, please download the GAF Historical Data Workbook.

Contact

Phone

Open M-F 9am- 5pm

Online

For questions related to your gas bill GasBilling.Inquiries@mass.gov
For other gas inquiries Non-BillingGas.Inquiries@mass.gov

Address

Department of Public Utilities
One South Station
5th Floor
Boston, MA 02110

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