Many investors focus solely on seeing their stocks grow in value. But as you get older, the prospects of getting some income from your stock holdings look more attractive. That's why dividend stocks have gotten so popular lately.

Many of the biggest companies in the world pay dividends, making it easy to find portfolio income from your stocks if you want it. But among the titans of the dividend growth world, you'll find a trio of stocks that few people know much about -- despite boasting some of the longest track records of rising dividends in the market. Below, we'll reveal three stocks that have delivered a combined 193 years of annual dividend increases and weigh their prospects for extending their streaks well into the future.

Company

Streak of Annual Dividend Increases

American States Water (NYSE:AWR)

65 years

Dover (NYSE:DOV)

64 years

Northwest Natural Holding (NYSE:NWN)

64 years

Data source: Yahoo! Finance, dripinvesting.org.

American States Water

The utility industry has always been a lucrative sector for dividend investors. Many utilities have highly predictable cash flows that leave them with extra capital after investing in building and maintaining their distribution infrastructure. Since before the Great Depression, American States Water has been operating water utility systems, and its growth over time has stemmed largely from its exposure to the California market and its population explosion.

For 65 straight years, American States Water has added to its dividend payouts, with its latest increase coming last August. The water utility hasn't been stingy with its hikes, either, giving investors a nearly 11% boost. With a dividend yield of just 1.4%, American States Water isn't the most generous dividend payer in the market. But a long history of steady performance demonstrates the water utility's reliability, and given California's booming economy, there's no reason to think American States Water won't see plenty of demand for its services for years to come.

Plant shoots growing from three piles of coins.

Image source: Getty Images.

Dover

Dover comes in just behind American States Water, with a 64-year streak of annual increases to its dividend. The industrial company has a mix of businesses that largely go unnoticed in the investing world, with specialties in engineered systems, fluids, and refrigeration & food equipment. The Illinois-based company has worked hard to bolster growth in its key segments, and both fluids and engineered systems have delivered organic growth in revenue and bookings that has offset weaker performance from food retail customers.

Dover's current dividend yield of 1.7% is below the market average, but part of that decline in yield has come from a soaring stock price on excitement that the company is seeking to focus more on its most prosperous business units. Last August's dividend increase of just a single penny per share amounted to a roughly 2% boost, but the potential for larger future dividend increases is there if Dover can capitalize more effectively on its best opportunities.

Northwest Natural Holding

Northwest Natural Holding is the holding company for natural gas utility NW Natural, which is based in Oregon and serves customers in the Pacific Northwest. With roughly 2.5 million people in its service areas in Oregon and southwestern Washington state, NW Natural operates natural gas pipelines and underground storage facilities, as well as provides water distribution and wastewater services.

With a yield of 2.5%, Northwest Natural is the most attractive stock on this list in terms of current dividend yield. The share price has also done well, reflecting the relative strength of the regional economy in its coverage area. As with Dover, Northwest Natural's dividend increases tend to be minimal, including its quarter-cent-per-share boost in October 2019. Even so, the utility company has a solid business model that should remain steady for years to come.

Bank on dividend growth

With nearly 200 years of combined annual dividend increases, these three stocks are favorites among income investors. They largely fly beneath the radar of big Wall Street investors, though, making them undiscovered plays for dividend investors seeking stocks with impressive pedigrees of performance.