Let's clarify the differences between S-traps and P-traps used in toilet plumbing.  Both are designed to trap water, creating a seal that prevents sewer gases from entering your bathroom.  However, their shape and connection points differ.   

An S-trap resembles the letter "S," connecting the toilet to a drain in the floor.  These were common in older homes.  While simpler in some installations, S-traps are prone to siphoning – the water seal can be sucked out, allowing odors to escape.  Modern building codes often discourage their use.   

A P-trap, shaped like the letter "P," connects the toilet to a waste pipe in the wall.  This design is more effective at preventing siphoning and is generally preferred by current building codes.  While installation might be slightly more complex, P-traps offer better performance and reliability.   

In short, P-traps are the modern standard due to their superior performance in preventing sewer gas leaks. S-traps, while sometimes encountered in older construction, are less desirable due to the risk of siphoning. The correct choice depends on your existing plumbing and local regulations. Consulting a plumber is always recommended for any plumbing work.

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Image Credit: BathOutlet.in