dig a trench and install channel and trench drain systems. the water will need to have a lower point to drain to and away from the property. 

@Dave Foster thank you for your reply I’ll dig a bit deeper and get it sorted out.

You try it on your own and are not seasoned the occupant living there now with an attorney will drag things out forever and cite all your mistakes in court.If you overpaid for this property see if there is a title issue or other technicality the selling bank did not follow where you can reverse the sale and require them to buy it back for what you have into it with purchase and costs so far.Get with a specialist attorney ASAP and not a generalist who dabbles in various legal categories.Would not make any contact with this tenant and let attorney handle it and the steps to follow as you do not have the experience and could likely dig a bigger hole to get out of for yourself.Good luck.

In a real life example though I was helping an acquaintance of mine who doesn't make much money and he hired a trencher for 75.00 to dig a 10" deep by 30' trench that he could have done in an hour and he had nothing better to do.

I use town tax acquired lists, realtor.com for house on market twice as long as normal, realtors that work with investors, and if you want to dig a little probate notices where property is involved.

I think I'll dig a little deeper into Boise and see what I can learn.  

I would dig a little deeper.  

Just got to dig a little.

Research and dig. 

You will have to do a little more research, dig a little deeper and turn a few more stones.