We're now more than 13 months into the COVID-19 pandemic.
For the first time in my 25 years at San Jose Water, we are temporarily taking our Montevina Water Treatment Plant offline due to low supply.
Currently, every billion gallons of purchased water has an incremental cost to the company of $4.2 million more than using our own supply sources.
As a direct result of the water supply outlook and in full transparency, we are announcing guidance of $1.85 to $2.05 per diluted share in 2021.
We are proud to have continuously paid a dividend for over 77 years and to have increased the annual dividend in each of the last 53 years, delivering value to our shareholders.
First quarter revenue was $114.8 million, a 1% increase over the first quarter of 2020.
Net income for the quarter was $2.6 million or $0.09 per diluted share, an 8% increase over net income of $2.4 million or $0.08 per diluted share reported in the first quarter of 2020.
The increase in diluted earnings per share for the quarter was primarily attributable to cumulative rate increases of $0.08 per share, cumulative cost savings of $0.04 per share, a tax benefit of $0.04 per share and an increase in nonregulated income of $0.03 per share.
The diluted per share increase was partially offset by a decrease in customer usage of $0.08 per share.
Customer credits in Texas totaling $0.02 per share issued in connection with the February Ice storm, a decrease in the availability of surface water of $0.02 per share and an increase in depreciation and amortization of $0.06 per share.
Our revenue decrease was a result of $2.8 million in decreased customer usage.
In addition, customer credits in Texas reduced revenue by $700,000 and net changes in certain balancing and memorandum accounts reduced revenue by $600,000.
These decreases were partially offset by $2.8 million in cumulative rate increases and $500,000 in revenue from new customers.
The minor reduction was primarily due to $800,000 in lower average per unit cost for purchased water, groundwater extraction and energy charges and lower usage, partially offset by a $700,000 increase due to the purchase of additional water supplies to supplement the lower level of surface water production we experienced during the quarter.
Other operating expenses increased $1.6 million or 2% for the quarter, primarily due to $2.1 million in higher depreciation related to utility plant additions, and $200,000 in higher maintenance expenses, partially offset by $400,000 in lower general and administrative expenses.
In addition, in the first quarter of 2020 we incurred $400,000 in merger-related expenses.
The effective consolidated income tax rates were approximately negative 52% and 15% for the quarters ended March 31, 2021 and 2020, respectively.
We added $46.7 million in company-funded utility plant during the first quarter of 2021.
This represents 20% of our total 2021 planned capital expenditures.
From a financing perspective, first quarter 2021 cash flows from operations increased 321% over the first quarter of 2020.
This change was primarily the result of a decrease in accounts payable and accrued expenses of $8.3 million, an increase in accounts receivable collections of $2.2 million and a $1.5 million increase in net income adjusted for noncash items.
In addition, in 2020, we made an upfront payment of $5 million to the city of Cupertino in connection with our service concession agreement and refunded $8.4 million to California rate payers that were accumulated in our 2017 Tax Act Memorandum Account.
In March 2021, SJW Group issued approximately $1.2 million -- I'm sorry, 1.2 million of new shares in an offering that raised net proceeds of approximately $66.9 million.
In addition, in April 2021, the company's California subsidiary entered into a $140 million credit agreement, and the company's Texas subsidiary entered into a $5 million credit agreement, both with JPMorgan Chase Bank.
At the end of the first quarter, we had $138 million available on our bank lines of credit for short-term financing of utility plant additions and operating activities.
The average borrowing rate on line of credit advances during the quarter was 1.42%.
As Jim just mentioned, we have already invested approximately 20% of our planned 2021 capital spending through the end of the first quarter.
San Jose Water's GRC application proposes a $435 million capital program for the years 2021 through 2023, supported by our award-winning enterprise asset management system.
A primary driver of the case is the $266 million in infrastructure investments that have been completed and are providing a benefit to customers, but are not yet covered in rates.
A 1.1% increase in the Water Infrastructure and Conservation Adjustment surcharge, or WICA, was authorized by PURA earlier this year and went into effect on April 1.
This covers $8.7 million in qualified infrastructure investments that have been completed and will provide incremental annual revenue of about $1 million.
The current cumulative WICA surcharge will be rolled into base rates, and the surcharge will be reset to 0 as part of the general rate case.
Maine Water filed a general rate case application for its Biddeford Saco rate division, requesting a $6.7 million increase in annual revenues with the Maine Public Utilities Commission, or PUC, in March.
The application is driven by a $60 million replacement of the 1,884 vintage drinking water treatment plant.
Connecticut Water is proposing a 15% discount on water bills for income-eligible customers that is similar to a program offered by San Jose Water since late 2005.
The acquisition added 230 new customers, gained additional water supplies to serve current and future customers and added rate base that reflects market value for future rate making purposes.
This was the 13th acquisition completed by SJWTX, which has tripled its customer base since 2006.
At the Board level, SJW Group is just one of 154 companies in the Russell 3000 to achieve a gender balanced board rating in 2020.
According to the 50/50 Women on Boards Gender Diversity Index.
Bob has served as a Director of the company since 2006 and as Lead Independent Director since 2015.

Summary:
As a direct result of the water supply outlook and in full transparency, we are announcing guidance of $1.85 to $2.05 per diluted share in 2021.
First quarter revenue was $114.8 million, a 1% increase over the first quarter of 2020.
Net income for the quarter was $2.6 million or $0.09 per diluted share, an 8% increase over net income of $2.4 million or $0.08 per diluted share reported in the first quarter of 2020.