Those in opposition of dam removal state that demolishing O'Shaughnessy Dam would take away a valuable source of clean, renewable hydroelectric power in the Kirkwood and Moccasin powerhouses; even if measures such as seasonal water diversion into the powerhouses were employed, it would only make up for a fraction of the original power production.
The remaining deficit would likely have to be replaced by polluting fossil fuel generation.
The removal of the dam would be extremely costly, at least $3–10 billion, and the transport of the demolished material away from the dam site along the narrow, winding Hetch Hetchy Road would be a logistical nightmare with possible environmental impacts.
Most importantly, San Francisco would lose its source of high-quality mountain water, and would have to depend on lower-quality water from other reservoirs – which would require costly filtration and re-engineering of the aqueduct system – to meet its needs.

The economic wisdom of removing the dam has been frequently questioned.
Some observers, such as Carl Pope (Director of the Sierra Club), stated that Hodel had political motives  in proposing the study.
The imputed motive was to divide the environmental movement: to see residents of the strongly Democratic city of San Francisco coming out against an environmental issue.
Dianne Feinstein, the mayor of San Francisco at the time, said in a Los Angeles Times story in 1987: "All this is for an expanded campground?
 ... It's dumb, dumb, dumb."
Hodel, now retired, is still a strong proponent of restoring Hetch Hetchy Valley and now-Senator Feinstein is still strongly against restoration.
The George W. Bush administration proposed allocating $7 million to studying the removal of the dam in the 2007 National Park Service budget.
Dianne Feinstein opposed this allocation, saying, "I will do all I can to make sure it isn't included in the final bill.
We're not going to remove this dam, and the funding is unnecessary."

Opponents of dam removal have pointed out that the flooding of the Hetch Hetchy Valley has also deterred the crowds that overrun other areas of Yosemite National Park.
Indeed, Hetch Hetchy today remains the least visited area of the park.
Karin Klein has described Yosemite Valley as "so crammed ... that it looks more like a ripstop ghetto than the site of a nature experience."
However, she does support breaching the dam once it has reached the end of its lifespan, and not replacing it.

In November 2012, San Francisco voters soundly rejected Proposition F, which would have required the City to conduct an $8 million study on how the flooded valley could be drained and restored to its former state.
The proposed study would also have been required to identify potential replacements for the water storage capacity and hydroelectric power production.
Those in opposition of dam removal state that demolishing O'Shaughnessy Dam would take away a valuable source of clean, renewable hydroelectric power in the Kirkwood and Moccasin powerhouses; even if measures such as seasonal water diversion into the powerhouses were employed, it would only make up for a fraction of the original power production. The remaining deficit would likely have to be replaced by polluting fossil fuel generation. The removal of the dam would be extremely costly, at least $3–10 billion, and the transport of the demolished material away from the dam site along the narrow, winding Hetch Hetchy Road would be a logistical nightmare with possible environmental impacts. Most importantly, San Francisco would lose its source of high-quality mountain water, and would have to depend on lower-quality water from other reservoirs – which would require costly filtration and re-engineering of the aqueduct system – to meet its needs.
The economic wisdom of removing the dam has been frequently questioned. Some observers, such as Carl Pope (Director of the Sierra Club), stated that Hodel had political motives  in proposing the study. The imputed motive was to divide the environmental movement: to see residents of the strongly Democratic city of San Francisco coming out against an environmental issue. Dianne Feinstein, the mayor of San Francisco at the time, said in a Los Angeles Times story in 1987: "All this is for an expanded campground? ... It's dumb, dumb, dumb." Hodel, now retired, is still a strong proponent of restoring Hetch Hetchy Valley and now-Senator Feinstein is still strongly against restoration. The George W. Bush administration proposed allocating $7 million to studying the removal of the dam in the 2007 National Park Service budget. Dianne Feinstein opposed this allocation, saying, "I will do all I can to make sure it isn't included in the final bill. We're not going to remove this dam, and the funding is unnecessary."
Opponents of dam removal have pointed out that the flooding of the Hetch Hetchy Valley has also deterred the crowds that overrun other areas of Yosemite National Park. Indeed, Hetch Hetchy today remains the least visited area of the park. Karin Klein has described Yosemite Valley as "so crammed ... that it looks more like a ripstop ghetto than the site of a nature experience." However, she does support breaching the dam once it has reached the end of its lifespan, and not replacing it.
In November 2012, San Francisco voters soundly rejected Proposition F, which would have required the City to conduct an $8 million study on how the flooded valley could be drained and restored to its former state. The proposed study would also have been required to identify potential replacements for the water storage capacity and hydroelectric power production.
Hetch Hetchy