How Much Cash Do You Actually Keep in Reserve?

I’ve never liked using one fixed reserve number because $50,000 can be extremely conservative for one portfolio and dangerously thin for another.

What matters to me is what that cash is actually protecting.

For a stabilized rental, I'd start with the expenses that keep coming whether the tenant pays or not: debt service, taxes, insurance, utilities you cover, HOA, management and anything else that is genuinely unavoidable. From there I'd look at the property itself. A five-year-old roof and HVAC system create a very different reserve requirement than a building where the roof, sewer line and mechanicals are all reaching the end of their useful lives.

That’s also why I don’t love rules like “keep six months of mortgage payments.” It’s easy to calculate, but it may have very little relationship to the risk you actually own.

If I have a duplex with an older furnace, a questionable sewer line and one tenant moving out in three months, some of the cash in my account already belongs to those problems even though I haven’t written the checks yet. I don’t consider that money available for another down payment.

Flips are a little different because the biggest risk is usually uncertainty in the scope and timeline. If I have a $100,000 rehab budget, I’m certainly not going into the project with exactly $100,000 available. How much extra I want depends heavily on what I’m doing. Paint, flooring and cabinets in a relatively known house are one thing. Opening walls in a 100-year-old building is something else entirely.

The older I get, the more I think reserves should be based on what can reasonably go wrong rather than a percentage someone gave you.

For a portfolio, I’d take it another step. I want to know what happens if more than one property decides to be annoying at the same time, because that’s usually how it happens.

Say one tenant stops paying, another unit turns over, and then an HVAC system dies. None of those is a catastrophic event by itself. If the combination forces you onto credit cards, a HELOC or a rushed sale, though, the portfolio was probably running with less liquidity than it appeared to have.

That’s probably my real “don’t go below this” test. I want enough cash that a genuinely bad stretch creates an irritating few months, not a financing emergency.

I also don’t count equity as reserves. It’s obviously valuable, and I absolutely consider it when looking at the strength of the portfolio, but $200,000 of equity doesn’t pay the plumber tomorrow morning. You still have to sell something or convince somebody to lend against it. I’d rather not have my emergency plan depend on what lenders or property values happen to be doing that week.

So when I'm deciding whether cash can go into another deal, I'd work backward. What are the plausible large expenses already sitting inside the portfolio? What does the next year of CapEx look like? What happens if collections get ugly for a few months? What would a bad construction surprise cost on the new project?

Once those things are covered, the remaining cash is much closer to what I’d consider genuinely deployable capital.

That can mean leaving a meaningful amount of money sitting in an account when another deal is available, which can feel inefficient. I don’t really see it that way anymore. The reserve is buying you the ability to make decisions on your own timetable.

There’s a huge difference between selling a property because you decided it was the best allocation of capital and selling one because two furnaces died and you need the money.

That difference is worth paying for.