After you've made an offer to buy a house, the seller will accept your offer, make a counteroffer with one or more changes, or reject the offer outright. We'll describe here how this will all play out.
First, it's important to realize that, whether yours is the only offer to have come along or one of many, a seller usually doesn't have to accept any particular offer. Many buyers assume that if they get their offer in before anyone else's, or theirs has the highest dollar figure on it, the house is theirs for the buying. But that's not so. In most states, it doesn't matter if your offer is the first or the highest -- the seller simply has no obligation to accept it. (An exception exists in a few states, where the seller must -- upon receiving a full-price offer with no contingencies -- either accept the offer or take the house off the market.)
Now, on with the post-offer timeline.
With any luck, after submitting the offer to buy a house, the first thing you'll hear back from your real estate agent is that the seller is interested in going forward. But that doesn't yet mean you're in contract -- that is, mutually bound to complete the sale. It's rare for a seller to accept a buyer's offer as written. More likely the seller will counteroffer, as described next.
Commonly, the seller will respond to your offer with a written counteroffer accepting some or most of the terms, but proposing changes to the:
You can accept the seller's counteroffer, reject it, or present a counter counteroffer. The negotiations will continue until either a deal or an impasse is reached. If you reach a verbal agreement on a deal, great -- but you're not in contract yet, nor bound to the deal.
Unless you're in a bidding war with other buyers, or you've submitted an absurdly lowball offer, it's unlikely that the seller will just say "No." Actually, the seller doesn't have to get back to you at all, but your real estate agents will probably be in contact, so that you'll find out the seller's response.
But, if you do get an outright rejection, your agent may be able to find out why. This will help you craft a stronger, more appealing offer next time you find a house you're interested in.
A contract is formed only when either the seller or the buyer accepts all of the terms of the latest offer or counteroffer from the other, in writing and with a signature, within the time allowed. Because every offer or counteroffer must include a signature, that basically means that you will have both signed on to the deal when the second party accepts the offer or counteroffer. Your two signatures indicate a mutual agreement and a binding contract.
At this point, if you have a change of heart and decide to back out for a reason that isn't covered in the contract contingencies, you'll forfeit any earnest money that you deposited along with your offer. That's not to say that you have no escape hatches. If, for example, your contract included an inspection contingency, and you discover after the inspection that the house needs more repairs than you're ready to deal with or negotiate over, you can cancel the deal.
If the seller backs out for a reason not covered by the contract contingencies, you can potentially sue for breach of contract and get damages. This may not be worth your effort, however, given that you've unlikely to be awarded the one thing you really wanted, namely, the house.
For a detailed analysis of how to negotiate the final house purchase contract and successfully navigate your way to the closing, see Nolo's Essential Guide to Buying Your First Home, by Ilona Bray, Alayna Schroeder, and Marcia Stewart.