Creating a pond?

It's coming in the next patch. (After almost 7? years)

Edit: Maybe I should say a patch before Cottage Living, because that doesn't come out until July 22nd. There might be more than 1 patch before then.

You can place the fishing ponds, but you'll need to go into debug. Be warned, though, they're huge. As for building your own, as @Anmirla said, we don't have that ability quite yet.

I can't wait! In Sims 3 base game (on Xbox), I created a lot that was a huge lake with two cottages on stilts over it and a common outdoors dining area. The kitchen and bathroom were their own buildings and the lake was stocked with every kind of fish and had a beach area for the play ground. It was my most favorite creation so when I came to Sims 4 and found that I could not do that, I was devastated to the point that I quit playing Sims 4 for several months while I wrapped my mind around the idea of not being able to put a lake or pond on different lots. Of course, there were other reasons too that I quit playing and disliked Sims 4.

Obviously I came back and honestly, still miss 3 but love 4 now. Ponds, if done right, will make me simply love 4 even more... if possible.