Medicare's top officials said in 2006 that they had reduced the number of fraudulent and improper claims paid by the agency, keeping billions of dollars out of the hands of people trying to game the system.

Fraudulent and improper payments have long bedeviled Medicare, a $466 billion program. In particular, payments for durable medical equipment, like power wheelchairs and diabetic test kits, are ripe for fraud.

In general, insurers say criticisms of claims-handling are unfair because most policyholders are paid promptly, and some denials are necessary to root out fraud.

There is no central government database that allows officials to monitor water tests by local systems.

The cooperation of NASCAR - or any other system, it turns out - persists only when everyone believes he has the opportunity to win.

Some officials overseeing local water systems have tried to go above and beyond what is legally required. But they have encountered resistance, sometimes from the very residents they are trying to protect, who say that if their water is legal, it must be safe.