I have helped buyers get into homes on Marin for 3.5 % down on FHA loans. We were able to close in 30 days. This type of loan requires mortgage insurance. The other viable loan product is the traditional 20% down payment. Interest rates are incredibly low right now.
... Yes... Like someone else said, talk to your lender..
Additionally, in a hot real estate market, anything less than 20% down will be difficult to get accepted. Most buyers in Silicon Valley today have more than 25 or 30% down, especially when many are all-cash investors...
You need to talk to lenders. The down payment you can make varies with the type of loan you get. I would talk to Ephraim Schwartz, partner at O'dette Mortgage Group, 415-297-8514 or email@example.com. Or go to my website http://www.sallyrosenman.com and go to Resources and look under Mortgage Brokers for many other excellent contacts.