possible water leak in crawlspace?

Lately my water heater has been running almost constantly, and yet we have hardly any hot water. There's a small patio outside our back door, and it has a chip near an external wall of my home, and yesterday morning I noticed steam rising from the small gap between the patio and wall due to the chip. Is it possible, or rather, likely, that a pipe from the water heater is leaking under the house into the crawlspace? Any advice would be greatly appriciated. Thanks!