Once you've completed the first three steps in the process of building your profitable tax lien portfolio, your real work begins. Now that you know where you're going to invest and you have the tax sale information and have a list of the properties that are in the sale, you can progress to step four to building your profitable tax lien portfolio, which is doing due diligence on the properties in the sale.

This is the most important step in the process and whether you do this properly or not could mean the difference between being extremely profitable and losing money on your investment. You need to do due diligence on tax sale properties before you bid at the tax sale. The exact procedures that you follow will vary depending on which state you are investing in and whether you are investing in tax lien certificates or tax deeds. You will have to be a little more rigorous when doing due diligence for tax deeds than you than you do for tax liens.

When you buy a tax lien, you are not buying the property, you are only paying the taxes and putting a lien on the property. But when you buy a tax deed, whether it is a regular tax deed or a redeemable tax deed, you are actually purchasing the property and you are now the owner of record. That means that you are now responsible for paying the taxes and any assessments on the property and you are liable for anything that happens on the property. If there is an environmental problem with the property, you're responsible for cleaning it up and that could cost you more than any profit that you might make on your investment.

Another reason that you'll want to check out tax sale properties for deed sales a little more rigorously than tax lien properties is that not all tax deeds are sold "free and clear" of any other liens. You may have been told that when you buy a property at a tax deed sale you are not responsible for any other liens on the property, like an existing mortgage, for instance. Depending on the state, this may or may not be true. Different states have different laws regarding what liens survive a tax sale. You need to know if there are any types of liens that do survive the tax sale and you need to look for them before you bid on a property in the sale. Even for liens that do not survive the tax sale, you still need to check to see that proper notification was given to all lien holders. If proper notification was not given to a lien holder before the tax sale, the lien holder could contest the sale.

Whether you are investing in tax liens or tax deeds you will still have to find the value of the property to make sure that it's worth it. You do not want to buy a tax lien certificate on a property that is not worth a few times what you your initial investment is. You have to plan on your expenses for recording your tax lien certificate, paying subsequent taxes for the duration of the redemption period (in states that allow you to pay them), and any foreclosure costs that you might incur if the lien is not redeemed. The property should be worth at least 3 times of what you determine your investment will be, taking all these expenses into account.

You can use one of two different methods to find the value of tax sale properties. You can find the tax assessment data, or you can check with a web site that gives recent sales prices of properties in the area. Some states have assessment data online. If the tax assessment information is not online, you will have to make a trip to tax assessor's office to find the information that you need.