Water leak going out of control

[Brandt Tingen]

Hi,  My tenant's water usage is normally 60 - 500 gallons per day.  I just looked at my bill and the water usage has been 3,000 - 7,000 gallons over the last few days.  I called the tenant immediately and asked what was going on and they said they had re-installed a new flapper but it was leaking.  Is it possible for a toilet to overflow this much, or does this much water have to be a burst pipe?  We have had very cold weather the last week and a half.  I asked the tenant what day they tried to repair the toilet and the day after is when the water usage spiked.  I have sent the tenant a letter reaffirming that they are to make no self-repairs under any circumstances, but looking for some ideas for now.  

Also these tenants are home all of the time, so if anyone recommends bomb-proof and leak proof toilet guts or kitchen sink faucets and parts, I would gladly take suggestions.  I am even open to installing commercial grade equipment.  

[Brandt Tingen]

It was the toilet valve running like a son of a gun.  Tenant rigged some type of rubber band contraption as a makeshift toilet flapper chain.  It was one of those modern flappers that is a cylinder that goes up and down as opposed to the traditional flapper.  Turned all the shut off valves and the meter came to a dead stop.  Turned on the toilet in question and it was running at 4gpm.  By my math that's more than 5,500 gallons per day.  

Learned a few very good lessons.  Number one sending a letter to this tenant and all other tenants stating with the process on shutting off shutoffs valves in the event of a leak and how to spot a leak.  Also reaffirming in the same letter that after a leak is contained, under no circumstances is a tenant authorized to repair the problem itself, to notify the landlord immediately, and that the landlord will have a plumber to repair the issue within 24-48 hours.  Number two is to add setting up high usage alerts with the water company in my lease-up playbook.  I usually do this on instinct but don't have it written down and the one time I forget is the time it costs me :[ 

Hoping I can appeal the water company after the plumber comes out and get that bill reduced. 

Will also be systematically replacing all of the shutoff valves a lot of them are questionable, and upgrading the toilets and fixtures over the course of the year.

Thanks for the great suggestions.