On Monday, September 12, 2016 at 12:56:22 PM UTC-4, wrote:
I am leasing an older home. Some of the outlets have the 3-prong
grounding outlet and many have just the two-prong which we use
adapters on. Can the regular two-prong outlets be replaced with
3-prong without rewiring the home? Thanks

If it's a two prong, ie no ground receptacle in an older home then there
is almost certainly no ground. You can't just replace it with a 3 prong,
ground type, but you can replace it with a three prong,
ground type receptacle if you install a GFCI and mark the receptacle
as GFCI protected, no eqpt ground. A GFCI breaker will protect all the
receptacles on the circuit. A GFCI receptacle will protect itself and
any other receptacles that are downstream of it and connected to the load
side of the GFCI. Those downstream receptacles may then be replaced
with 3 prong, ground type and marked as described.