"The ability of the organizations to manage this tremendous volume of need and with their infrastructure -- they can only do just so much at any given time," Ken Berger, President and Executive Director of Charity Navigator said.
Some of the explanation for why groups are not spending more of their donations at the moment is intentional planning.
"There's a conscious effort to have a certain amount dedicated to the immediate and then a significant amount for the longer term," Berger said.
"This is common for large-scale disaster response efforts by reputable NGOs. For example, for the Asia tsunami response, World Vision spent approximately 40 percent of its response budget in the first year of its multi-year relief and recovery response," said Rachel E. L. Wolff, spokeswoman for World Vision.
But there's more to it than that.
Organizations might be able to get more help to Haiti if there were better coordination, Berger said.
The U.S. government is coordinating its government money through U.S. Agency for International Development. The U.S. State Department says the United Nations is in charge of coordinating the global relief effort.
The United Nations has tapped former President Bill Clinton to coordinate its efforts. But when ABC News called Clinton's office, a spokesman said Clinton "is not operationally in command" of distributing aid in Haiti.
There are also political sensitivities involved. The Haitian government is ultimately in charge of its country, but the government was weak to begin with and further decimated by the earthquake.
The bottom line? A Red Cross relief worker in Haiti told ABC News no one is in charge. He said they are waiting for someone -- anyone -- to step up.
Holding back donation money has slowed down certain aspects of the aid effort.
Nine out of ten people who need shelter don't have a proper tent to sleep in, and the tropical rainy season is just a few weeks away.
"We need to have improved structures for everyone before the hurricane season," said Kristen Knutson of the United Nations Office for the Coordination of Humanitarian Affairs (OCHA).
According to OCHA, there are more than 1.2 million people living in so-called "spontaneous settlements," and nearly half a million who have fled Port-au-Prince, putting added stress on neighboring towns.
Because of all of the crowding, there is no room for showers and toilets. So far, there are only 900 latrines for 900,000 people who need them in Port-au-Prince.
There are some bright spots on the ground -- food distribution has picked up. Approximately, two million people are in need of food and 2.2 million have received a two-week supply. Still, many Haitians complain of shortages.
Clean water, according to OCHA, reaches nearly 800,000 people a day.
The delivery of relief supplies is also going more smoothly. Roads are open, the port is being repaired and the traffic coming into the airport is half of what it was two weeks ago.
The biggest concern now is that disease could overwhelm hospitals still packed with earthquake victims.
It is still a challenge to organize and distribute all of this aid in a disaster area the size of Yellowstone National Park. Everyone we spoke with said Americans should not be disheartened that some of their donations remain in some charity's holding docks.