Water features offer year-round enjoyment in the landscape, even in winter. Since the Portland area is blessed with fairly mild winters, very little is needed to protect your water feature from the elements. Except for hard freezes, you should be able to keep the feature running. In fact, the constant movement of water helps delay freezing.
Keep an eye on the weather forecast. If a hard freeze is coming it’s a good idea to turn it off. If all the water freezes while the pump is running, it will likely get damaged or burn out. If your pump is in a reservoir below 6″ of water it shouldn’t need to be removed. Otherwise, take the pump out and store it indoors for the winter. In a typical rock bubbler, the pump is usually in the corner of the reservoir, underneath a removable screen and a layer of river rock.
If your fountain has an urn that collects water, empty it. Water will expand when frozen and may cause the urn to crack.
If you have an Auto-Fill Kit attached to your fountain you will need to winterize it too. It’s best to shut off the water at the source feeding the auto-fill. Shut off the water from the source and then leave the auto-fill valve in the “open” position. Also, make sure all the water is drained from the auto-fill itself since it’s above the water level and thus susceptible to freezing and breaking.