How do I find the water main entry point to my house?

Question

My house has no apparent main water line shut off valve. Usually one would find a shut off valve right near where the water main entered the house structure. At my current house I have never been able to determine where the water main entry point is located.

I have a house that has a lower level that is on a slab level with my garage. The other 2/3 or the house is built over a crawl space. I have checked the crawl space and found no water line entry points there. It is not possible to see where the water lines are routed in my house because they are all embedded in walls and ceilings that are covered over with drywall. Even my garage area, furnace area, water heater area and laundry room are all finished over with drywall. Thus I have no idea where the source point for my water lines is located.

It is possible the water main comes up through the slab of the lower level of the house and immediately goes up into a wall where it is hidden away from view. It is equally possible that the line enters below ground level at the periphery of the house and not findable unless I decided to dig a deep moat all around my house.

Currently if I want to shut off all the water in my house I have to use a T-bar handle to shut it off by the street near the water meter. This would be a less than ideal situation in the case of a water leak emergency. It is just not feasible to expect family members to be able to find the T-bar handle and run out to the street to turn off the water. For this reason I want to find the water main entry point and install a proper shut-off valve.

I am looking for suggestions about how to go about finding the water main entry point to the house. And hopefully there is a suitable method that works without having to rip down tons of drywall.

* Some Added Comments *

The water meter is out by the street under a concrete cover about six inches from the curb.

The water meter is at the extreme corner of the lot to the side of the driveway away from the house.

The water company's input ends about about six inches over the edge of the curb!!

The house was built in ~1987.

Answer 1

Everybody wants to save money

Builders and utility companies are not in the business of wasting money, which means the main line will be as straight and as short as possible. This is a big help to you, since it will narrow your search. Walk out to the curb shut off, and look back at your house. Try to determine the straightest, shortest path between the curb shutoff and the house. Now you'll have a general idea of where the line enters the home.

Trace the line

In most cases utilities bury a tracer wire in the trench above utility lines, to make the lines are easier to locate later. If you call 811 (assuming you are in the US, though I believe this service is offered in other areas as well), they should be able to send somebody out to locate the line for you. This will show you the approximate path the line takes to the house.

Don't let pipes freeze

Because it's a water line, it will likely enter your house below the frost line. If you can determine the frost depth in your area, you'll have a more targeted area to search.

People are idiots

It's not uncommon for people to do dumb things, especially when they don't know how dumb they are. Water meters and shutoffs are ugly, and nobody wants them in their newly remodeled living space. It's possible that your valve has been walled up, and you'll have to remove some finish material to find it. Look in closets, and keep an eye out for access panels.

If only you had X-ray eyes

There are a few tools that can help you search a wall where you suspect the valve might be. A stud finder should be able to locate pipes in the walls, depending on the stud finder you buy. A metal detector will find anything metal, so that could also come in handy. If you've got a bunch of cash to throw around, a thermal camera may be able to actually see the pipe through the wall.

Where does service enter?

After reading the update to the question, and then reading through building code. It seems that it may be possible that there is not a shutoff valve where the line enters the building.

International Residential Code 2009
P2903.9.1 Service valve. Each dwelling unit shall be provided with an accessible main shutoff valve near the entrance of the water service. The valve shall be of a full-open type having nominal restriction to flow, with provision for drainage such as a bleed orifice or installation of a separate drain valve. Additionally, the water service shall be valved at the curb or property line in accordance with local requirements.

According to this, there must be a shutoff valve "near the entrance of the service". However, in most cases the water meter has to be near the "entrance of the service" too. In your case, it may be that the "entrance of the service" is at the property line, and not at the building. So there may actually be no shutoff valve inside the house.