TMZ broke the story ... Kanye had 4 dome-like prototype structures built on the 300 acres of land he owns in Calabasas. He hopes to create a whole community of new-age homes -- dome-like structures that break class barriers.

Here's the problem ... we've learned several neighbors have complained to the L.A. County Dept. of Public Works, and after inspectors came out to the property they determined the project violates the building code, and if Ye doesn't get the property permits by Sept. 15, the structures must be torn down.

Here's what we know. On July 18, one of the neighbors contacted the Dept. and said there was construction on the property late at night. An inspector came out and spoke with the site manager, who said the domes were part of a "production" and they were temporary structures. If they're temporary, building permits are not required.

The Dept. got another call from a neighbor a week ago, again complaining of construction noise. The inspector came out again, and saw the domes were sitting atop a concrete foundation. For that and several other reasons, the inspector determined the structures did not appear temporary.  As a result, plans and building permits are required, and Kanye and Co. never applied for them.

So, the Dept. of Public Works is now demanding that Kanye and Co. submit plans and get building permits within 45 days, or else. The "or else" -- tear them down.

A source close to Kanye tells TMZ ... the structures were always intended to be temporary, because they're simply prototypes. The source says they are in touch with the County and intend to comply with the requirements. And, the source adds, the concrete base was necessary to secure the structure for safety and structural reasons but will eventually be removed along with the structures.