Generally speaking, the restroom is clean when you walk into it and it meets your specific cleaning standards. Below is a list of specific things you would want to see when entering a clean restroom.
All dispensers are clean and correctly filled with the appropriate supplies.
All restroom fixtures are clean and free of all soils, smudges, fingerprints, marks, oils and other residues. All toilets and toilet seats are clean, dry and free of all soils, urine, body fluids, spots, splatters, stains and other residues. All urinals and urinal screens are clean, dry and free of all soils, urine, body fluids, spots, splatters, stains and other residues. All sinks and drinking fountains are clean, dry and free of all water spots, soils, splatters, soap deposits and other residues. All floor drain covers are clean and free of soils, lint, mop strings, dirt and other residues.