Dividends are paid at the discretion of a company's board of directors. So a good starting point when looking for safe dividends is a long history of annual dividend increases. It shows a corporate commitment to regular and growing shareholder distributions. You'll also want to pay attention to a company's business model, as dividends can only go up if a company does well over time. If you are trying to find safe dividends, try looking at Dividend Kings Procter & Gamble (PG -1.04%), Federal Realty Investment Trust (FRT -0.98%), and Black Hills (BKH -1.38%).

Let's find out a bit more about these three companies that offer shareholders safe dividends.

1. P&G is an expert at milking cash cows

Consumer staples giant Procter & Gamble owns iconic brands (like Bounty and Crest) in product categories that are always in demand. The reliable cash from sales to consumers who are loyal to P&G products fuels the company's impressive 67-year annual streak of dividend increases.

That makes the company a Dividend King. But the really important factor to consider here is how P&G supports its products. Virtually all of the categories in which P&G competes involve mature and existing products that more than adequately provide for consumers' needs. At the same time, people like to change on occasion too and P&G invests heavily in research & development so it can entice customers to keep coming back to get the new and improved product, while often paying more for something that is roughly similar.

The power of the words "new" and "improved" can't be overstated when it comes to consumer products. Being able to draw customers to stores is another leg up for P&G with its retailer customers, which also value the company for its strong marketing and distribution chops. 

Procter & Gamble's dividend yield is around 2.4% today, which is roughly the middle of the road historically speaking. While the stock is not a screaming buy, conservative investors might be happy to pay a reasonable price for a great company.

2. Federal Realty has the longest dividend record of any REIT

Federal Realty is proud of its 56-year streak of annual dividend increases. One of the big reasons for that is that it is the only real estate investment trust (REIT) on the Dividend King list. In fact, it has the longest annual dividend streak of any REIT. It achieved such success by being very boring.

Essentially, Federal Realty is a strip mall landlord (it also owns mixed-use developments) with a focus on location, location, location. Its property portfolio is located in population-dense regions with wealthy residents. The mix of population and wealth compared to peers is way above average. Retailers like to be located in areas where there are a lot of people capable of spending a lot of money. Meanwhile, roughly 75% of Federal Realty's properties contain grocery stores, which brings customers back again and again. And management is constantly investing in the portfolio to make sure its properties hold leadership positions in the regions they serve.

Federal Realty's dividend yield is roughly 4.2% right now. It's not trading at bargain basement levels, but if dividend consistency is what you care most about it could be a great fit for your income portfolio.

3. Black Hills operates in growing markets

Black Hills' dividend yield is around 4.4%, which is near the highest levels of the past decade. Of this trio of Dividend Kings, it is probably the most attractively priced. The dividend has been increased for 53 years in a row.

The company operates regulated natural gas and electric utility assets in eight states. Being regulated means that it is granted a monopoly in the areas it operates, but that it has to get rates and investment plans approved by a government entity. Generally speaking, regulators ensure that Black Hills earns a reasonable return on its investments as it works to provide reliable energy to customers. But the interesting thing here is that the customer growth within the utility's core regions is nearly three times the national average. That's a particularly advantageous position for a utility to be in, as more customers mean more revenue.

Black Hills will not excite you, it is a utility, after all. But if history is any guide, strong customer growth should allow the company to keep paying you well for owning it.

The proof is in the dividend history

Procter & Gamble, Federal Realty, and Black Hills all have incredible records when it comes to dividend growth, with each falling into the Dividend King category. Usually, the safest dividend is the one that's just been increased (though that's not always the case). With these three stocks, the dividend gets increased year in and year out, with each of their dividends backed by a strong business model. If you are looking for the safest dividend yields in the world, you'll want to get to know each of these companies a little better today.