If we feel our rental home in unsafe and/or unhealthy can we leave immediately?

Our rental home has no smoke detectors or fire extinguisher(sp). The water leaves nasty stains on all the dishes, toilets, and sinks. If you pull back the carpet in multiple places throughout the house you can see outside. If its very cold outside its impossible to keep the house warm because of all drafts even with all the heaters on. Our roof is leaking in multiple spots. Everyone says to tell the landlord and let him fix everything, but we just want out. We have no lease and the landlord makes us pay in cash. It seems fishy to us. Can we just leave without a notice?