To answer the first question, anywhere. A slogan can come from solid business rationale or complete randomness. Take "Just Do It." for example, it’s a slogan that's provided athletes the ultimate (and most simple) motivation for almost 30 years. It's creator - Dan Weiden - said it came from notorious serial-killer Gary Gilmore's last words before facing a firing squad: "Let's do it." That's some interesting (and maybe even dark) inspiration, to say the least.
Effective slogans usually has a few things in common. To start, they're usually simple and have a clear message. Secondly, people tend to like slogans with a higher level of creativity. And lastly, a slogan should fit the brand and business that it is attached to. Failure to do this last part will leave potential customers confused and disengaged.
And with that said, here are the best irrigation slogans.