Is it necessary to use a water conditioner if I were to age tap water. I know I have seen it mentioned somewhere on the forum before that over time the chlorine will disperse or something like that when the water is left in a bucket.

depending on how your water is treated it might need prime still as they use diff chems to clean out there pipes/systems from time to time ext ext.

If one is certain that tapwater is treated with only chlorine, then leaving water to set for 24 hours would allow chlorine to dissipate.
However, here in U.S. much of drinking supply is treated with chloramine which is chlorine/ammonia.
For this water,, it would be wise in my view to use dechlorinator that addresses not only chlorine,but ammonia as well.
Some say that chloramine treated water could be safe after setting for a week, and other's who perform smaller water changes in larger tank's, or planted tanks, don't treat water at all and let plant's or biological filter deal with the ammonia from chloramines. But surely chlorine and or ammonia is easily addressed with use of conditioner such as PRIME so it is what I choose to use whenever I change water from tank's .

Yeah I have been for the past 4 months just doing my water changes with untreated unaged tap water with no ill effect. In my 120 gallon tank. But i dread the day that my city decides to send some chemical down the pipeline and wipes out a tank full of fish. Also wanted to see if the little bit of chlorine that might be in my tap water even though it doesn't show up when tested I have would dissolve if left for a while. Also is there a test for chloramine or do you just test for chlorine and then ammonia?

I just use PRIME and no need for any testing.
Once or twice a year here,they increase the chlorine content to flush lines and is why I choose to use dechlorinator for all new water I add to the tank's from the tap.
Water company sometimes announces their intent to increase the chlorine level's with notice in local paper.Other times they don't.

You can also try contacting them to find out what they put in the water.

I have a handy "what's in the water" sheet that my water company mailed to me recently.

Like others said, that doesn't protect you from surges when they put extra crap in the water to flush things out. I age my water and also use prime. I look at it this way: By aging and using prime, I make sure that the water has no chlorine/ammonia/nitrite, and the insurance really isn't that expensive. BTW along the process of aging the water I also heat up to the right temperature.

I think a good rule of thumb is to always use Prime or one of the other chlorine/chloramine removers.

In Louisville, for instance, the switch to chloramine from chlorine occurred without any public notice. So you never really know when something could occur.

Better safe than sorry. And dechlor products are cheap.

How would you all suggest doing this when doing a water change of 40-60 gallons of water though? On a smaller tank it seems a lot easier. Just wondering how I go about it just fill her up after dosing prime or vice versa. Or is it necessary to age the water as well?

I keep a 15gal storage tote filled with aged & dechlor'd water for small tanks.

But for larger tanks, I add Prime/whatever as I'm adding the water. Usually add the dosage amount to a 5gal bucket, fill it up and pour it in.

nope, no need to let it stand you can just dump it in. i have not treated tap water for long periods in the past with no ill effects and i still do top ups without treating the water. my neighbor, who used to have 39 tanks did water changes without treating the water and never had problems.

Leaving tap water untreated if you're immediately adding it to your tank is a bad idea.

Primarily - as stated above - unless you know precisely what's in your water, you run serious risks.