Tenant complaining about limited hot water

[Maxwell Servais]

I have a tenant in my 4-unit property saying that hot water runs out after about 10 minutes. I have turned up the water heater to the highest temperature available, but it does not seem to have fixed the issue. None of the other tenants have mentioned anything about hot water running out, but this tenant says she used to have enough hot water to bathe herself and her dog, and now it runs out after about 10 minutes. 

Any advice on some additional improvements that could be done to potentially fix this problem without having to buy a new water heater? Water heater is about 5 years old. Thanks in advance!

[Andrew Kubik]

I would check the temperature if your water to make sure it's heating up to the right point. How big is your tank? I would make sure to have at least 40 gallons. is this unit further away from the hot water heater than the rest of the units? If so, that could be causing the drop in temperature. Make sure to have your pipes insulated also. Lastly, it might have to do with the water fixture itself. If the reducer was taken out of the showerhead, it could cause the hot water to flow much more quickly than intended.