A nonprofit effort to purchase and preserve the last major freshwater spring in Honolulu with a surface connection to the ocean has run into a jam after neighboring homeowners expressed concerns over their privacy.

The Maunalua Fishpond Heritage Center and the Trust for Public Land secured $2.3 million from city and state land preservation funds earlier this year to help buy a neglected residential estate in Kuliouou that contains a roughly 1,000-square-foot natural pool known as Kanewai Spring which feeds fresh water to Kanewai Fishpond.

But the city’s portion of the money is in danger after some residents who own property bordering the fishpond recently told City Councilman Trevor Ozawa that they have privacy concerns.

There are nine property owners surrounding the fishpond, including Punahou School and Miss Paris Beauty Academy Inc.

The other owners are Linda and James Yeomans; Kirsten, Michael and Richard Melcher; Paula Ogi and Stacey and Stephen Shimamoto; the Tran-JMT Family Trust; and a Nevada company called Kalanianaole Highway LLC, managed by Claire and Richard MacDonald. The state also owns one vacant parcel.

Ozawa, who represents East Honolulu, said he hopes that the two nonprofits and the concerned residents can resolve the issue today. But if they can’t, Ozawa said, he would like to keep the city’s $1 million contribution out of the city budget that’s up for final approval Wednesday because he said it would be irresponsible of him to rush forward with a budget item for the property acquisition without addressing the concerns.

The councilman recommends deleting the $1 million through a proposed floor draft of the budget bill if an amicable resolution can’t be reached between the neighbors and the two nonprofits.

However, Ozawa also said he hopes the two sides can resolve the issue at a meeting today that he plans to attend.

“I think there’s an agreement we can reach,” he said, adding that if no resolution is reached today, then the parties can continue to work on it and perhaps move ahead with the purchase next year.

Yet if the opposition stands after today, pulling the $1 million jeopardizes the purchase — and potentially the spring.

The two nonprofits have a purchase agreement that needs to be completed by Aug. 31. If the deadline isn’t met, the owner of the estate with the spring can pass up the deal with the nonprofits. The nonprofits fear if they miss this chance, a real estate developer could buy the property and destroy the spring.

The spring, whose name, Kanewai, means “water of the Hawaiian god Kane,” nurtures numerous species of baby native fish, including opae, oopu, aholehole and pipiwai, by providing fresh water to the adjacent fishpond, which is connected to the state-owned Paiko Lagoon Wildlife Sanctuary, which leads to Maunalua Bay.

The property also includes a historic coconut grove of more than 50 trees, a one-tenth interest in the fishpond, a fishpond sluice gate and a fishing stone shrine where fishermen would make offerings to Hawaiian gods.

Last year the Historic Hawai‘i Foundation added the spring to its list of the state’s most endangered places.

The city Clean Waters and Natural Lands Commission awarded the $1 million for the spring’s acquisition. Another $1.3 was provided through the state’s Legacy Land Conservation Program. The $350,000 balance for the $2.65 million purchase is being raised by the two nonprofits.

Community support for the preservation effort included an endorsement from Hawaiian sailing canoe navigator and Niu Valley resident Nainoa Thompson, who said in a letter that eight generations of his family have lived in the Niu and Kuliouou region.

“We have watched the change in our environment and community and are now looking at an amazing movement to honor, protect and restore our valuable places,” he wrote.

Ozawa emphasized that residents who own property fronting the lagoon want to protect the water resource but have concerns about the size and frequency of groups visiting the property for what the nonprofits envision will become a cultural education center.

The nonprofits propose tearing down a deteriorated 3,357-square-foot mansion dating from 1948 and building a new structure containing a classroom, community gathering space, caretaker’s residence and Maunalua Fishpond Heritage Center office.

The old home was once owned by convicted Hawaii Ponzi schemer Ronald Rewald and is now held by Japanese taxi company Rikuo Kotsu Co. Ltd., which let the spring fester and become overgrown to the point where water was choked off from the lagoon.

The Maunalua Fishpond Heritage Center obtained permission from Rikuo to clean up the property with volunteers from schools and community groups working every third Saturday of the month for the past five years.