In your contract it should be marked off what kind of sewer system you have on there.Also, if you're removing the tank, it's important it is properly removed and an environmental test is done to make sure there are no contaminants. 

Wrong, well two of them are in a part of dc that is rapidly declining & no one in the family wants to take care of (and he certainly cannot) and has deferred maintenance on both, the other two are beachfront and a block from the beach, one already got it by a hurricane (no damage, but did trigger a special assessment & insurance skyrocketed) the other one just being near saltwater for 70 years takes a toll on a place, the other thing that happen’s with real estate over time is appreciation eventually rapidly outpaces rent growth so these aren’t as big cash flows as you’d think, a decision is was made to keep these properties both for appreciation and of course stepped up basis (most of these properties he bought for nothing and then depreciated the hell out of) while he has great assets and it will all be fine in the ends and we are all very lucky he has the assets to cover my grandmothers care, frankly trying to figure all this when he’s 88 and everyone is stressed just isn’t ideal, he probably should have just 1031’d up certain properties that had environmental and/or let’s just say locational risk into new or very new construction in the easy to rent burbs like a decade ago, while the tax implications always make selling at tough proposition, I think at a certain point in everyone’s life especially if there are lucky enough to have kept properties for decades should transition them into these easiest assets they can find in their market (you can even put in a reit or more specifically a Delaware statutory trust) to make thing’s easier for them and their family once they are no longer capable of managing those properties themselves. 

For instance, while it can bolster initial cash flow by reducing tax liability, it could diminish deductions in subsequent years (when the property might produce better cashflow), impacting overall tax footprint, so you need to take into account all that in the context of your short term and long term tax strategy (e.g. if you plan on selling soon, at which time the depreciation gets recovered, or not and planning to hold for a long term/forever/1031, buying more later and creating more depreciation to offset cashflow or not, etc.).The alternative is a do-it-yourself (DIY) or survey option, which costs around $400 to $500 per property (I can do my CSS report in 10min, once I have all the data needed).

In the event of a failed inspection, the Santa Cruz County Environmental Health Department will be notified.

Without knowing what the environmental risk they were addressing in 1970 it's hard to help you.

Our footprint is expanding west so I’ll be needing to learn a ton of information about new states.Fixing a title issue from 1874 likely requires a lot of work*… the original parties (other than gov’t) are almost surely unavailable.

My garage was a similar foot print; he shared the blueprint he followed; I was sure I could do this.But self-doubt crept in: Could I do it?

It can't be manufactured or mobile home and of course we'd have to do all the permits and if I'm coverting an existing building I'd have to have it engineered and permitted to meet code and environmental health requirements.

Buy the biggest lot you can find.Build the biggest footprint you are allowed. 

Major code or environmental or building and safety violations carry over to the new owner (that's you) - stick to the easy stuff. - Those are some initial things to think on.