A note on the company's home page on Tuesday said the site was "temporarily unavailable." Although available earlier in the morning, the site was inaccessible around 11 a.m. PDT. Washington Mutual's site was also inaccessible for much of the day on Monday.
"All existing bill payments and automatic transfers will be processed as scheduled," the company said in its note. "We regret any inconvenience and thank you for your business."
Washington Mutual spokeswoman Libby Hutchinson said in an e-mail that she didn't know why the Web site was down but that the company's technology staff was trying to resolve the problem. Hutchinson didn't have an estimate for when the site would be back up.
"We regret any inconvenience to our customers but encourage them to use our customer call centers to transact business during this time," Hutchinson said.
Last month, banking giant Wells Fargo battled its own Web site problems, experiencing twoin four days. The company blamed the downtime on "network connectivity" issues.
Recent research reports indicate that Net users are increasingly using online banking and spending greater amounts of time with financial services Web sites. Outages can frustrate consumers, preventing them from accessing their account information or from paying bills.
Although Washington Mutual's main Web site was down on Monday and Tuesday, its sites that serve home loan, investment and insurance customers were still available.