Whether it's through stocks, bonds, ETFs, or other types of securities, all investors love seeing their portfolios score big returns. But when you're an income investor, your primary focus is generating consistent cash flow from each of your liquid investments.Cash flow can come from bond interest, interest from other types of investments, and of course, dividends. A dividend is the distribution of a company's earnings paid out to shareholders; it's often viewed by its dividend yield, a metric that measures a dividend as a percent of the current stock price. Many academic studies show that dividends account for significant portions of long-term returns, with dividend contributions exceeding one-third of total returns in many cases.Southwest Gas in FocusSouthwest Gas (SWX) is headquartered in Las Vegas, and is in the Utilities sector. The stock has seen a price change of 10.63% since the start of the year. The natural gas company is currently shelling out a dividend of $0.6 per share, with a dividend yield of 3.54%. This compares to the Utility - Gas Distribution industry's yield of 2.86% and the S&P 500's yield of 1.29%.In terms of dividend growth, the company's current annualized dividend of $2.38 is up 5.5% from last year. In the past five-year period, Southwest Gas has increased its dividend 5 times on a year-over-year basis for an average annual increase of 5.63%. Any future dividend growth will depend on both earnings growth and the company's payout ratio; a payout ratio is the proportion of a firm's annual earnings per share that it pays out as a dividend. Southwest Gas's current payout ratio is 47%. This means it paid out 47% of its trailing 12-month EPS as dividend.Earnings growth looks solid for SWX for this fiscal year. The Zacks Consensus Estimate for 2021 is $4.15 per share, representing a year-over-year earnings growth rate of 0.24%.Bottom LineInvestors like dividends for many reasons; they greatly improve stock investing profits, decrease overall portfolio risk, and carry tax advantages, among others. It's important to keep in mind that not all companies provide a quarterly payout.For instance, it's a rare occurrence when a tech start-up or big growth business offers their shareholders a dividend. It's more common to see larger companies with more established profits give out dividends. Income investors have to be mindful of the fact that high-yielding stocks tend to struggle during periods of rising interest rates. With that in mind, SWX is a compelling investment opportunity. Not only is it a strong dividend play, but the stock currently sits at a Zacks Rank of 3 (Hold).Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Southwest Gas Corporation (SWX): Free Stock Analysis Report To read this article on Zacks.com click here.