Southwest Gas Storage Company

First Revised Volume No. 1

Effective Date: 12/15/1999, Docket: RP00- 58-000, Status: Effective

Original Sheet No. 30 Original Sheet No. 30 : Effective

RATE SCHEDULE ISS (Continued)

INTERRUPTIBLE STORAGE SERVICE

3.5 Annual Charge Adjustment Provision (ACA)

Shipper shall pay the ACA Unit Charge which has been assessed by

the Federal Energy Regulatory Commission pursuant to Section

382.202 of the Regulations. The ACA Unit Charge shall be

reflected on Sheet No. 5 of this Tariff and shall be added to the

respective Volume Injection Charge component of Southwest's rates.

4. MONTHLY BILL

The monthly bill for storage service shall be the sum of the applicable

storage charges as defined in Section 3.1, the ACA Unit Charge, and an

Authorized Overrun Charge, if applicable.

5. RESERVATIONS

Southwest reserves the unilateral right from time to time to make any

changes to or to supersede, the rates and charges and other terms in

this Rate Schedule ISS and the other provisions of Southwest's FERC Gas

Tariff, and the applicability thereof, subject to the provisions of the

Natural Gas Act, the Natural Gas Policy Act and the Commission's

Regulations thereunder.

6. GENERAL TERMS AND CONDITIONS

The General Terms and Conditions of Southwest's FERC Gas Tariff are

applicable to this Rate Schedule and are hereby made a part hereof.