Step Heights
For scale purposes, "normal" steps should be no higher than 8 units. However, the maximum value that a player may step up is 18 units (just keep steps 16 units or lower).

Normal Jumps
The maximum height for barriers the bots will jump on is 32 units.

Water Jump Heights (or "Everyone, out of the pool!")
The maximum distance that a bot may jump to exit water is 18 units. This is the height difference between the water surface and the adjacent floor that the bot is jumping onto. If the water jump height is made higher, human players will have a hard time getting out of the water.

Rocket Jumps
With normal gravity and without the quad, the maximum rocket jump height is around 280 units (you can sometimes jump a few units higher but this is a safe value for reference). In practice, except for especially tricky jumps, this value should be substantially lower. Test rocket jumps repeatedly before settling on a final height.

Math for Map Makers
Here's some math to calculate some other values of interest:

Gravity = 800;
Jump velocity = 270;
Max vertical rocketjump velocity = 670;
Max run velocity = 320;
Max step height = 18;
Max jump height = 0.5 * gravity * (jumpvelocity/gravity)*(jumpvelocity/gravity);
Max normal jump height = 45 units
NOTE: even though this is the mathematical maximum jump height always keep the the 32 units maximum barrier height for bots in mind when building maps.
Maximum horizontal jump distance over a gap from one spot to another when both are at the same height:

t = sqrt((maxjumpheight + maxstep) / (0.5 * gravity));
t = 0.3986 seconds;
dist = maxrunvelocity * (t + jumpvelocity / gravity);
dist = 235 units;

Because players use a bounding box we can jump a full bounding box width further in the ideal case. (15 units at the jump starting position and 15 at the landing place).

235 + 15 + 15 = 265 units.

Again, remember that this is the mathematical maximum which players can only reach under ideal circumstances.