Hoover dam was built in the 1930’s and we know that infrastructure deteriorates with time. So when will it need significant repair or replacement?

No expense was spared in the quality of the design and construction of Hoover Dam.

It is an arch dam. Arch dams are the Cadillac of dams in terms of meticulous construction.

What we can observe is that the maintenance of that dam is performed dutifully. A lot of dams suffer problems because their maintenance budget declines and events that could have been prevented do happen.

Another thing that bodes well for Hoover Dam is its age.

Arch dams distribute a great deal of energy in to their sides or wings. If these begin to deteriorate over time due to leakage, erosion, or material failure the dam no longer can operate as designed. We don’t see that at Hoover. It is old enough now that if it were going to develop a critical problem in the foundation or sides, we would have seen it by now.

There is much more transparency in dam safety of government dams like Hoover. It might develop a problem that requires repairs beyond the maintenance budget. If it does, appropriating the necessary money will inform the public of the general nature of the problem.

Spending a few tens of millions to save a billion dollar dam is an easy logical sell. It is financially prudent. But our legislators frequently make financial decisions on saving high capital projects that defy logic.

Hoover might need repairs next year or not until 200 years. Aside from replacing aging mechanical parts there is no way to know.