 Ms Harman's home was one of five where the wifi network was tested |
Google's popular Street View project may have collected personal information of members of Congress, including some involved in national security issues.
The claim was made by leading advocacy group, Consumer Watchdog which wants Congress to hold hearings into what data Google's Street View possesses.
Google admitted it mistakenly collected information, transmitted over unsecured wireless networks, as its cars filmed locations for mapping purposes.
Google said the problem began in 2006.
The issue came to light when German authorities asked to audit the data.
The search giant said the snippets could include parts of an email, text, photograph, or even the website someone might be viewing.
"We think the Google Wi-Spy effort is one of the biggest wire tapping scandals in US history," John Simpson of Consumer Watchdog told BBC News.
Drive-by spying
The group conducted an experiment to highlight the vulnerability some users expose themselves to by retracing the same routes, used by Street View cars, to detect unencrypted or open networks.
 The Street View car takes photos for the service |
This practice is often described as "drive-by spying" and is favoured by criminals who trawl the streets to find houses or businesses using unencrypted wifi, so they can steal financial information.
Google has stressed all along that someone would need to be using the network as their cars passed by and that the in-car wifi equipment automatically changes channels roughly five times a second.
Consumer Watchdog focused on a number of high profile politicians whose homes appear on Google's Street View maps.
It found that Congresswoman Jane Harman, who heads the intelligence sub committee for the House's Homeland Security Committee, has an open home network that could have leaked out vital information that could have been picked up by Street View vehicles.
Ms Harman's office has not responded to calls for comment on the issue. Consumer Watch said it did not collect any information but did pinpoint where unsecure networks could be found.
"Our purpose was to show that members of Congress are targets just as much as every other citizen in the land" said Mr Simpson.
'Concerns'
The experiment found that a further four residences it checked had vulnerable networks in the vicinity that may belong to members of Congress.
This included the home of Congressman Henry Waxman, chairman of the Energy and Commerce Committee, which has jurisdiction over internet issues.
 The ability to tap into open networks is a major security issue |
His office told BBC News that "Chairman Waxman has previously raised concerns about Google" which were contained in a letter sent to company chief executive Eric Schmidt in May.
At that time, Mr Waxman said the Committee was "interested in the nature of this data collection, the underlying technology your fleet of Street View cars employed, the use of the information collected, and the impact it could have on consumer privacy".
The Computer & Communications Industry Association, CCIA, said the tactics used by Consumer Watchdog left a lot to be desired.
"What Consumer Watchdog did was not a useful contribution to what could and should be a broader online privacy debate," said CCIA president Ed Black.
"They detected unsecured wifi networks that anyone, including neighbours, can pick up. It proves nothing about what, if anything, a person or company like Google might have done to intercept and record data."
'Major progress'
Consumer Watchdog wants Congress to hold hearings on the issue and ensure that Google boss Mr Schmidt be made to testify under oath.
In a statement, Google wrote "as we've said before, it was a mistake for us to include code in our software that collected payload data, but we believe we did nothing illegal. We're continuing to work with the relevant authorities to answer their questions and concerns".
That includes German authorities who said it was still waiting to receive a copy of data gathered by the Street View cars.
The office of Johannes Caspar, the head of the Hamburg Data Protection Authority, told the BBC that a deadline set for earlier this week was extended at Google's request because of the recent 4th of July national holiday.
"We expect some - and hopefully major - progress early next week," said spokesman Ulrich Kuhn.
