Ryan McGonigle and his grilfriend, Iara Cologis. Issues involving underground tanks have twice blocked his efforts to buy a home.

Ultimately, for one reason or another [they] just died on the vine, McGonigle says. Some were quick and merciless; others lingered for a few months while both sides kind of weighed their options.

Buyers, sellers and agents agree that in today’s market, all sides need to be wary of the most common deal breakers: environmental concerns, the need for major repairs and conservative appraisals that can jeopardize a mortgage loan.

Underground oil tanks broke two of McGonigle’s house deals. Real estate lawyers, inspectors and agents say that tanks even when drained and filled with virgin sand and soils, then certified by a lab are common deal breakers.

The bottom line for many lenders, agents and lawyers: Remove it. Towns are much more vigilant than they were 15 or 20 years ago, tanks will continue to rear their presence in future sales and environmental concerns are much more mainstream.

I treat tanks so seriously, that to me it’s black and white, says real estate lawyer Richard Kelly. We can’t even talk about having a tank.

In addition to tanks, inspections can uncover issues typically, larger-ticket items like a roof or furnace that needs replacing, or structural problems that can kill deals if buyers and sellers cannot successfully negotiate credits or who will handle repairs.

Inspections are crucial to home sales yet are the cause of many problems. Depending on how the initial negotiation plays out, sellers may feel they got less than they deserve, and buyers may feel they paid more than they should, says Amy Sprechman-DeBellis, office sales manager for Abbott & Caserta Realtors in Ho-Ho-Kus. Negotiating issues that are found in inspections can be painful for both sides, she says.

Adds Kelly: The key thing now for deals falling apart comes down to expectations and whether or not the expectations of the buyer or seller are unreasonable.

In a soft market, many buyers believe sellers are desperate and will do anything, from repairs to upgrades. Sellers feel they have often gone as low as they can go on price.

Agents agree that doing an inspection before listing is a good idea, though sellers don’t always want to take on the expense. Others want to be as informed as possible so that they know how any repair or replacement issues might affect pricing.

Joe Monaco of All State Home Inspection in River Edge says that before the market downturn, he averaged several prelisting inspections a week. Now, he typically conducts a few a month.

Several years ago, Abbott & Caserta developed a program called the Certified Home, which, for a fee, has a house inspected before going on the market. It includes a one-year warranty that covers the seller until closing and then covers the buyer for a year, as well as flood certification, title search, two hours of handyman services and staging. About 30 percent of clients have used the service, Sprechman-DeBellis says.

Once something is discovered, it must be fully disclosed.

One of McGonigle’s deals that collapsed involved a house in Rutherford, which, according to the owner, did not have an underground tank.

However, McGonigle says, the inspector saw signs. A tank sweep was done, and sure enough, there it was.

When he demanded that the tank be taken out, the sellers complied. When he asked to do soil borings to check for oil leakage, they refused.

I can’t take on liability blindly, says McGonigle, an intellectual- property and trademark lawyer.

Currently under contract for a house in Bergen County, he’s much closer to the altar: Soil samples related to this underground tank came back clean.

While larger concerns can and do break potential deals, agents and lawyers note a deal is as much about the individuals involved, and it can go either way.

For Bobby Sherrow and his family, the glass turned out to be half full during negotiations for a home in Oakland, which they ultimately bought and moved into last August. The house needed a septic system, says Sherrow, a contractor. We were looking for a credit. They wouldn’t give me full credit, but they met me halfway.