The water in my apartment is only lukewarm in the mornings and sometimes at night. (everywhere- shower, sink, kitchen) The landlord says it is because other people in the building are taking a shower, using the sink, etc. and this high demand is affecting our hot water supply. Is this a legitimate reason or is he dodging potential plumbing costs? We live in a 4 story walk up with 6 apartment units in Brooklyn. I doubt all 6 apartments have their shower running at 7am every morning and even if so, why can't all units be guaranteed to have hot water at the same time?

Thank you!

It is possible.
Ask him to turn the water heater up to the hightest level, there is danger of scalding so be careful, it will produce the same volume of water, but the higher temperature will allow it to go further. He could also add another hot water tank, or install water saving nozzles in each shower which truly do work, and in some cases feel even better than a water waster. The shower nozzles would be a cheap solution for him.

I will therefore assume there is only 1 large HW Heater for all the apartments. There is not enough capacity for the water temp to be recovered. He has a valid but poor answer, a bigger or another heater would be the solution. Turning up the temp, while it may produce more hot water, opens up a lawsuit for burns.

There is level you can turn it to where it won't scald, it will allow it to go further. The nozzle and another tank would be a comprehensive solution.
The lawsuit liability would be the landlords not the renter.

Helpful?