Yes, it is quite possible. The Environmental Protection Agency (EPA) states that most leaks within homes go undetected.

Fixing a leak can be quick and easy, and often doesn’t cost much. For example, a leaky toilet flapper can cost less than $5 to fix, but can save more than 200 gallons per day. For more information about pinpointing and fixing household leaks, read the Fix-a-Leak information section and view the Fix-a-Leak Brochure.

Yes, under certain conditions water leak adjustments may be made for leaks that have been repaired or for exceptional unexplained increases in consumption that have been validated by a plumber and/or Public Utilities Meter Operations staff. A leak adjustment may occur only after a leak has been repaired and may require a verified meter read by the City of Raleigh's Public Utilities Department. Administrative fees will not be adjusted. Leak adjustments will cover no more than a two-month consecutive period. Only one financial adjustment associated to billed usage will be allowed each year per customer per premise.