Typically everything is negotiable, especially here in California. There are some situations where the SELLER must pay certain closing costs, and this arises when the loan being used to purchase a home is a government loan such as FHA or VA. VA loans typically have high fees that are mandated to be paid by the seller, sometimes up to 1% of the loan amount.
The only closing costs a buyer usually MUST pay without negotiation is the title insurance that is required by the buyers lender to fund a loan.
Industry norms in California:
Closing Costs - Buyer and Seller are each to pay own (escrow fee, etc)
City/County Transfer Fees - Seller
HOA Transfer Fees - Seller
Seller's Title Insurance - Seller
Alta Title Insurance for buyer's financing - Buyer
Natural Hazard Disclosure Report - Seller
Termite Inspection / Section 1 repairs on WPA - Seller
Section 2 repairs - Buyer
Retrofit requirements (water heater, smoke detector, low flow water fixtures, etc) - Seller
Buyer's Basic Home Warranty (3rd party provider) - Seller
I hope that helps!
San Diego Real Estate Specialist
Residential Sales and Appraisal