The only way you're going to be sure, is with a pressure test.
This isn't as complicated as it looks. Simply turn off the water supply to your house (outside in the pavement/garden), then connect the tester to the rising main.
You'll have to find where it comes in, and disconnect it from the house plumbing.
Pump up and watch the guage.
http://www.hss.com/g/...-Pressure-Tester.html