300 g/hour at night?? wow.

You can contact Ashoksan Water Services at 718-499-4008 Maybe they can determine what your problem is.

We haven't found anything obvious but we are looking. I would think 300 gal per hour would be quite obvious. Other ideas... broken meter, roof tank overflow, other??

Two issues here to address, faulty meter/or water is leaking. I would address both simultaneous. Have someone check the water meter while at the same time instuct the staff to check the building from top to bottom. If there are no visable signs of water like you mentioned it sounds like a fixture is open.Well trained staff would know to pay attention to such as they do their daily chores. I have had similar situations in the past mostly due to running toilets. Thankfull other vigilant unit owners or staff reported the problem. Hope this helps.

MRM

Thanks for feedback so far. Last nights usage (38 apartments).

11 pm: 90CF (673 gallons)
12 am: 60CF (449 gallons)
1 am: 70CF (524 gallons)
2 am: 50CF (374 gallons)
3 am: 60 CF (449 gallons)
4 am: 40 CF (299.2 gallons)
5 am: 40 CF (299.2 gallons)

Check your boiler as well.
The water tank feeding it for steam might have an issue.

Just a thought.

A single running toilet can waste 2 gal/minute (120 gal/hr, 2880 gal/day). If you have only a few running toilets, that could account for your usage.

We instituted an energy audit for our building a couple of years ago which looked at running toilets and dripping faucets in every apartment (along with making sure radiators were installed properly, windows and doors were tight), with the super fixing anything that wasn't working properly for free (up to $25/apt for supplies). Worked great, and caught several problems.

Shareholders and tenants were very cooperative, since it helped us keep maintenance costs down.

VP11104 was correct in his advice. I would communicate your concerns to either the management company or the company that services your heating plant.

I would also recommend you contact the company Bright Powers. Google them for contact info...they are local with an office in NYC. I have no vested connection to them, yet we have consulted with them on many issues ranging from Benchmarking to engineering studies. I've pointed you to them, they will point you in the right direction.