David, is this a new noise? I had an old Jabsco pump onboard my boat when I purchased it, they are fairly noisey, they are also shock mounted and make a D D D D D D D sound when running, if they have a broken mount or something is lying up against them they will sound like a maching gun.

I installed a Shureflow pump that modulates its output on demand, it is much quieter making low wwwwrp noise when it comes on. It also puts out about four time the flow and pressure.

B B B B BY

If you haven't already done it, This is a very easy upgrade. You can see more in the article in upgrades on plumbing system makeover.

The air sound described is usually attributed to empty water tank(s). Either that or your pump diaphragm is starting to go.

I generally find that when something on the boat starts making a new noise, particularly an "irritatingly loud" noise, it is either broken or about to break. Might just be me, but an ounce of prevention....and so on.

Dave,
Tara also has a Shurflo Extreme Smart Sensor 5.7 pump, now…
Prior to the newer variable speed, demand-sensing pumps, an expansion tank (AKA Accumulator Tank) was installed down-line from the pump. This tank helped maintain a consistent line pressure and prevented the pump from rapidly cycling (making various sounds in the process).
If you have an accumulator tank (Tara had one, originally), the tank may need to be re-pressurized. There is a schrader valve (just like your tires) on the tank that you can use a tire pump to add air. The pressure to pup up to depends on the pump specifications. On Tara, prior to replacement, I would turn on the pump, open a faucet and pump enough air (plus a “little” more) until the hammering noise stopped.
Tiring of that maintenance drill, I replaced the old Shurflo 220 pump with the new smart sensing Extreme 5.7 and trashed the accumulator tank.
Now we have a very quiet pressurized water system (Can’t hear it), about 60 psi at the faucets and some spare storage area next to the water pump.
Hope that helps you, Shipmate.