You would like a high quality reverse osmosis water but are limited because your landlord does not want you to drill through granite.
Here are a few ideas:
1) You could tell your landlord that this will increase the value of his property.
2) Sometimes there is already a hole for a soap dispensor or a sprayer. These holes can be used for reverse osmosis faucets.
3) You could replace your current faucet with a dual purpose faucet.
Hot & Cold Dual-Function Classic Chrome Faucet for Reverse Osmosis Systems, FCT-AQUA (GKD01) ,
Hot & Cold Dual-Function Contemporary Chrome Faucet for Reverse Osmosis Systems, FCT-MODENA (GKD02)
4) You could use a countertop system. You might not want to use the merllin as a countertop (unless for a very short term) because it is quite large. Instead, you could use a countertop reverse osmosis system:
Countertop Reverse Osmosis Drinking Water Filtration System RC540T50 and Counter Top RO Water Filters
Thank you,
WaterFilters.NET