Am I missing a chimney cap?

[Lucas Hammer]

So there is water leaking into my tenant's unit on the first floor and I'm wondering if it could be a chimney cap issue. The roof is really hard to get on top of but I was able to get the attached picture. The water heater vents into the chimney and the chimney has a concrete decorative top, but am I right in assuming that I should be able to see a cap as well here? If so, does anyone recommend a company that could affordably install one for me? I'm on the Southwest side of the city in Little Village. Thanks!