Ever stepped out to a pool and thought that something about it just doesn’t seem right? Sometimes it’s wisest to trust your instincts. Whether public or private, a swimming pool may not be safe for you or your children to swim in. Here are the seven signs you should be on the lookout for.

1. Cloudy Water

Water that is a little cloudy isn’t something to scoff at. Cloudy water may have high mineral content, which makes chlorine less effective. Low chlorine levels lead to bacteria and viruses in the water. They may be anything, from salmonella to cryptosporidium. Plus, cloudy water may have other debris in it, it’s hard to tell.

2. Dirty Water

Dirty water is more obviously unsafe than just cloudy water. Among the leaves, dirt, and other sources of discoloration, more dangerous pathogens may be hiding.

Streaks of green and black goop may indicate that algae is growing in the pool. While not usually a health danger itself, algae helps hide contaminants from chlorine and isn’t pleasant to get on your skin.

Water may have become dirty if the pool’s filter and pump aren’t working. If so, what are the chances the chlorine has been properly dispersed?

4. Rusted or Cracked Parts

Whether it’s the pool liner or the pool equipment, nothing should be rusted or cracked. Bacteria can hide in the crack of pool liners. Also be careful of any rough spots of rust or parts that are sticking out where they shouldn’t. You could cut yourself as your brush by. If you don’t cut yourself on it, someone else has and their blood is in the pool.

5. Missing Safety Equipment

You should do a quick survey of the pool equipment before you get in. Afterall, you don’t want to first notice that safety equipment is missing when you need it. Look for pool fences and flotation devices even in private, backyard pools. If this is a public pool, they should have a defibrillator and equipment to help people with disabilities to get in and out of the pool.

6. No Lifeguard

A lack of professional supervision is also a problem at any pool. If this is a public pool, consider if there are enough lifeguards—one is not enough for most public pools. In someone’s backyard, designating one adult as a lifeguard is a good idea. But, be sure that person has been trained as a lifeguard, especially in child CPR. Otherwise, be prepared to save your child yourself.

7. Too Many People

It sounds counter-intuitive but having too many people in a pool can be dangerous. First, they bring in bacteria, dirt, debris and other contaminants with them. The pool owner needs to boost the chlorine to make up for this high volume. Otherwise, the water quality drops quickly, potentially to unsafe levels.

While this may be more common in backyard pools as people hold summer parties, public pools may be guilty of letting too many people in the water too. Or, they may simply forget to adjust for low chlorine levels.

Before you step into any pool, whether it’s a well-established public pool, or your own backyard pool, be sure it’s safe.