Marieke Knight is a firm believer in conserving water. She doesn't water her lawn. She doesn't leave her taps dripping. That's why when the Saskatoon resident's water bill was nearly $4,000 last month, she was in complete shock.

"I didn't believe I read it right. I checked over it and checked over it and thought surely there was a mistake," Knight said.

Knight's water bill typically costs her $280 a month. The huge spike has had her scrambling. When she contacted the city to get a clarification she was told the bill was no mistake.

It was based on her actual water consumption.

Leaky toilet may be to blame for million litres of wasted water

Knight said she did have a leaky toilet in the basement suite she rents out, but replaced it in September.

Marieke Knight's water bill for November 2017 shows her owning nearly $4,000 (Chanss Lagaden/CBC)

She calculated she would have had to drain out nearly a million litres of water to make up the huge bill, something she said is unlikely.

"The amount of water that the city said I've used is a million litres, just under a million litres. I did the math and it's about 250,000 milk jugs just dumped out," she said.

The massive bill came after Knight sent in her meter reading to the city after a year of not doing so.

She had been paying her bills monthly, but those were only estimates.

The nearly $4,000 bill was for the extra water the city claimed she used in the year.

Plumber surprised by huge spike

Shane Cyrenne, a plumber with Perfection Plumbing, said he's heard of leaky toilets causing spiking water bills, but still found Knight's massive bill to be suprising.

"That's definitely excessive," he said.

Cyrenne said for a toilet to waste that much water it would have to be going "full blast" with the flapper up.

Knight said her toilet was leaking for a maximum of a month and no flapper was up or broken.

According to Cyrenne, a normal leaky toilet will make a bill go up, but not by not that much.

"In a month, I would hard pressed to say that caused a $4,000 water bill,' he said.

Raising the alarm

Knight said she has now been checking her water meter diligently. She will never go a month without sending her reading into the city, she said.

"My concern is really for people who this does happen to; not just myself. They said it's a common problem and that's really why I want to get the word out," she said.

The city also recently decided to cut her bill in half. She said is grateful, but her bill is still nearly $2,000. That's nearly ten times what she regularly pays.

Despite her complaints, Knight said she is going pay the bill.

City says bill could be from watering lawn, leaky toilet

In a statement, the City of Saskatoon said it does not comment on specific cases. But it does say a discrepancy between what someone is being charged based on estimates and an actual reading can cause a huge spike.

"In the past we have seen large bills due to increased watering during a dry summer, or changes such as how many people are in the household, or failing appliances and fixtures – like a toilet – that leak," the statement said.

The city says the new automated system being installed in most homes will fix the problem in the future.