A bill pay system wherein participating consumers pay bills to participating billers through a payment network operating according to preset rules. The participating consumers receive bills from participating billers (paper/mail bills, e-mail notices, implied bills for automatic debits) which indicate an amount, and a unique biller identification number. To authorize a remittance, a consumer transmits to its participating bank a bill pay order indicating a payment date, a payment amount, the consumer's account number with the biller, a source of funds and the biller's biller identification number, either directly or by reference to static data containing those data elements. Bank C then submits a payment message to a payment network, and the payment network, which assigns the biller reference numbers, forwards the payment message to the biller's bank. For settlement, the consumer's bank debits the consumer's account and is obligated to a net position with the payment network; likewise, the biller's bank receives a net position from the payment network and credits the biller's bank account. If the consumer's bank agrees to send non-reversible payment messages, the consumer's bank does not submit the transaction until funds are good unless the consumer's bank is willing to take the risk of loss if funds are not good, in the case of a guaranteed payment network.