Stainless steel pool ladders that have rusted or pitted are often a result of low ph in chlorine pools or too much/too little salt in salt water pools.
Types of Stainless Steel: There are 2 main groups of stainless steel that your pool ladders could be made from. If you have a salt water pool you should have “marine grade” type 316 stainless steel ladders to prevent rusting. They do cost more, however the added corrosion resistance is the only way to go for salt water pools.
To prevent rusting: Make sure your pool is grounded properly when it is built. This will prevent galvanic corrosion which could rust you pool handrails and ladders. Keeping you ph in balance is also very important. Low ph (acidic) could damage your hand rails and pool ladders even though they are stainless steel. This is partially due to the fact that they are submersed and are not able to for the protective oxide layer which is formed in the presence of oxygen. Keep your pools ph level in the recommended range of 7.2-7.6