The two lines that break California DSCR files: property tax and insurance

Reassessment is a purchase event, not a refinance event

Prop 13 sets a base year value and limits annual increases to the assessed value, with the base resetting when the property changes ownership. That single mechanic explains most of the gap between what a seller pays and what a buyer pays. If the seller bought decades ago in a market that has since repriced, the current bill can be a fraction of what the county will bill the buyer.

A refinance is a different event. Generally it is not a change of ownership, so the base does not reset simply because you refinanced. The exceptions are worth knowing: a transfer into or out of an entity can be a change of ownership based on the ownership interests involved, and completed new construction or substantial improvements can trigger a supplemental assessment regardless of any transfer.

For underwriting, the practical rule is to model the taxable value the county will use after the transaction, not the value on the current bill. Where a purchase is involved, that is generally close to the price. Where an entity transfer is involved, it is worth confirming with the county assessor rather than assuming.

Mello-Roos, parcel taxes and the fixed charge problem

California tax bills carry more than the base levy. Voter-approved debt service, city and county parcel assessments, and community facilities district special taxes all land on the same bill. Mello-Roos districts are common in newer master-planned communities — parts of the Inland Empire, Sacramento County, San Diego’s eastern tracts and Placer County — and the special tax can run for decades.

What makes these charges dangerous for DSCR is that they are largely fixed. A special tax of several thousand dollars a year is the same whether the property is worth more or less than you paid, and whether it is occupied or vacant. On a higher-value coastal property that is an inconvenience; on a lower-value Inland Empire or Central Valley property it can be a meaningful share of the monthly housing cost, and it moves the ratio more than a small change in the interest rate would.

The fix is procedural: pull the actual tax bill for the parcel, identify each line, and keep the special assessments in the denominator. Do not model a percentage of value and call it taxes. On a condominium, also read the HOA budget for special assessments that are being collected, because those behave the same way.

• Base levy versus voter-approved debt versus parcel assessment versus CFD special tax
• Whether a CFD is still outstanding and for how long
• Supplemental assessments from recent construction or a prior transfer
• Any assessment bond being repaid through the tax bill

The insurance market, described honestly

California’s insurance market has contracted. Several carriers have limited new business or withdrawn from wildfire-exposed areas, and underwriting on older homes has become stricter — roof age, electrical panel type, plumbing material and brush clearance all matter. Where the standard market will not write a policy, the FAIR Plan provides basic fire coverage, usually with a separate difference-in-conditions policy to restore what the FAIR Plan excludes.

For an investor, the sequence matters. A FAIR Plan dwelling policy plus a wrap is often more expensive than the standard policy the seller had, and the seller may have held that policy for years under terms no longer available. Using the seller’s premium as your model is therefore optimistic in exactly the cases where it matters most.

The other California-specific fact is that a standard policy is not a rental policy. A tenant-occupied dwelling needs landlord coverage, and a short-term rental needs rental-use coverage that acknowledges transient occupancy. A policy that does not match the use is a claim denial waiting to happen, and it is also a closing condition on many loans.

Flood, fire and the third hazard nobody prices

Flood is excluded from standard policies. In California it matters in specific places: the Natomas basin and American River corridor in Sacramento, parts of the Central Valley, coastal and bayfront areas, and the desert washes around the Coachella Valley. A required flood policy is a real monthly cost, and it belongs in the coverage math whenever the parcel sits in a mapped zone.

Wildfire hazard severity zones are mapped by the state, and the maps are used by insurers as well as by local brush-clearance requirements. A property can be in a moderate zone and still be declined by a specific carrier based on its own modeling. That is why a quote for the exact address is worth more than any rule of thumb about the neighborhood.

The third hazard is earthquake, which is not covered by a standard policy and is usually a separate decision with a separate deductible. Most California investors decline it and accept the risk; that is a legitimate choice, but it is a choice, and a condominium HOA master policy may already carry a deductible that owners are assessed for.

The order to model it in

Start with rent, because it sets the ceiling. Then the tax line at post-transaction assessed value, including everything on the bill. Then a real insurance quote for the specific address and use. Then HOA dues. Then solve for the loan amount that leaves the coverage where you want it. Doing it in the other order — picking a loan amount and then checking whether the property works — is how investors end up paying for appraisals on files that were never going to close.

If the coverage is short after the honest numbers, the levers are the loan amount, the property, or the structure. Not the tax estimate, and not the insurance premium.