We currently live in a 5 year old home that has three bathrooms. Now, the problem persists in our Master Bath. After you use any water source in the bathroom, the toilet makes a rushing air noise (for a second or two) every 5 minutes. It subsides after about 45 minutes.

I looked in the toilet tank and waited to see what it does. When it makes the noise it shoots a squirt of water out the side of the pump thing (not sure of the proper term) through a small hole?

Is this an $$$ fix? Please help!