We know that the anointing oil was
there because he instructed the priest and prophet to take Solomon down to Gihon and anoint him there (1 Kings 1:33-35).
So…when David says in Psalm 36:8-9 ‘they are abundantly satisfied with the fulness of your house, and, you give them to drink from the river of your pleasures, for with you is the fountain of life’, the picture is of the site he had created with the tent or tabernacle at the Gihon Spring. Gihon is 'the river' and 'the fountain' at the 'house.'
That site, known as HaMakom throughout the Old Testament was recognised by David as the ‘X’ spot of history which God had marked to the Patriachs with His presence. When he gave his son Solomon the plans God had put in his heart (1 Chronicles 28) it would have been for near the Gihon/HaMakom site where the ‘river of God’ flowed. In my view Gihon’s gushing waters were piped up to service the temple requirements for copious washings. It provided the type of the ‘living water’ that flows at the throne of God.
See details by clicking on 'THE PLACE HaMakom; where Jerusalem's temples stood'