H2S is produced by anaerobic bacteria in the water. They grow in hot water. It's harmless but the smell can be pretty rank. It's most common in wells since most city water is treated.
An aluminum rod can help but it's not guaranteed. The real fix is a powered rod but they're more expensive, like 3 to 4x more. Since it's a rental, you probably wouldn't want to go that way unless you can talk your landlord into paying for it.
