Here is one ActiveCaptain review for anchoring in Spa Creek:
If you want to see Annapolis and dont want to pay the big bucks, this is perfect! ( If you need work done, anchor in Back Creek) Annap. makes it so easy for cruisers! Every street end has a free dinghy dock, set in amongst beautiful multi million dollar homes. It is an easy 3 - 4 block walk to Main Street, Church circle, State circle etc. Naval Academy is 6 blocks. I left my bike at the dock for several days, and parked our truck at night and over the weekend, here as well. Daytime parking is limited to 2 hours. The harbor master boat cruises through the anchorage and you can register with him (no charge). The pumpout boat, comes through frequently, (CH 17) is only $5.00. Showers at Harbor Masters office (Ego Alley) are only $1.00, laundry there as well. Yacht Club lets reciprocal YC members shower for free.On south side of the creek is Truxton Park with docks,trails,swimming pool, and club. Great kayaking. Only hard part is finding enough room between the mooring balls - but dropping the anchor vs $40 a night on a ball - easy decision and we found a perfect spot.