Why does water come in on the passenger side floor on my 2008 Kia Spectra?

Water entering the passenger side floor of your 2008 Kia Spectra could be due to a clogged or damaged windshield drainage system, allowing rainwater to leak inside. It may also be caused by a faulty door seal or a malfunctioning heater core, which can lead to coolant leaking into the cabin. Inspect the weather stripping around the doors and Windows, and check the drainage channels for blockages. If the issue persists, consider having it examined by a professional.