How to Check a Flood Zone Before Quoting

Why this matters

A condenser quoted at grade in a mapped flood zone can come back from plan review needing a platform three feet high, a different air handler location and a new electrical route, and the quote that won the job no longer covers it. The flood map, the community's freeboard rule and the house's elevation certificate decide that before anyone sets a pad, and all three can be read from the office in about fifteen minutes. This procedure is the lookup. What the answers require of the equipment, the base flood elevation, the federal trigger and the substantial-improvement rule, is owned by the resilience cards. See related: Flood Zones, Base Flood Elevation and Equipment.

The procedure

1. Pull the effective map panel for the address. Search the address on FEMA's Flood Map Service Center. It returns the effective Flood Insurance Rate Map (FIRM) panel that covers the property, its panel number and its effective date, and lets you generate a FIRMette, a printable excerpt of the panel around the address. FEMA's National Flood Hazard Layer viewer shows the same effective data on an aerial base, which helps place the house. Reason: the panel number and effective date are what the floodplain administrator and the plan reviewer will ask for, and "the map says" means nothing without them. A map a customer printed years ago may have been superseded since.

2. Read the zone at the building, not at the lot. A zone boundary can cross a lot, leaving the house in one zone and the back yard in another. Read the zone where the equipment will sit. The common designations:

• A, AE, AH, AO are Special Flood Hazard Areas, land with a 1 percent annual chance of flooding. AE carries a base flood elevation (BFE); AO carries a flood depth in feet instead; plain A has no BFE determined on the map.
• V and VE are coastal high-hazard areas where waves add to the flood. Equipment rules are stricter there.
• Shaded X is the 0.2 percent annual chance area, and unshaded X is minimal flood hazard on the map. Neither is a Special Flood Hazard Area, and neither means the lot cannot flood.

On an AE panel, BFEs are printed along wavy lines at whole-foot intervals. When the building sits between two lines, the community either interpolates or reads the flood profile in the Flood Insurance Study; ask which in step 5 rather than guessing. Reason: the equipment rule depends on the zone at the equipment, and a whole foot of BFE can decide whether a platform is needed.

3. Check for a Letter of Map Change. The Map Service Center lists Letters of Map Change (LOMCs) issued against a panel after it took effect. A Letter of Map Amendment (LOMA) removes a specific structure or parcel from the Special Flood Hazard Area, usually because a survey showed it sits above the BFE. A Letter of Map Revision (LOMR) changes the map itself, often after a drainage project; a LOMR based on fill (LOMR-F) covers ground that was raised. Read what the letter covers: a LOMA for the house does not necessarily cover a detached garage or the yard where the condenser is going. Reason: a LOMC can move the house out of the zone, and the panel image will not show it.

4. Check for preliminary or pending maps. On the Map Service Center, look for preliminary FIRM data for the community. Many communities are partway through a remapping, and once the new map takes effect, work permitted after that date is judged against it. Some communities already regulate to preliminary BFEs where they are higher. Reason: a quote that meets the current map and fails the one taking effect before the permit is issued is a quote that gets re-priced at plan review.

5. Call the community's floodplain administrator. Every community in the National Flood Insurance Program designates someone, often in the building or planning department, to administer its floodplain ordinance. Ask, in this order: the zone and BFE they show for the address; the freeboard their ordinance adds and the resulting design flood elevation (DFE); whether their rules apply to replacement equipment, or only to new construction and substantial improvements; whether they track improvements cumulatively over a period of years; and whether they have an elevation certificate on file for the address. Reason: the federal rule is a floor, and the local ordinance is where freeboard and the replacement-equipment question are actually decided. The resilience card explains the layers; this call finds out which version applies here.

6. Decide whether you need an elevation certificate. An elevation certificate is FEMA's standard form on which a licensed surveyor, engineer or architect records the elevations of a building's lowest floor, adjacent grade and the lowest machinery or equipment servicing the building, in the same datum as the BFE. Ask for one when the building is in a zone with a BFE and the job places, replaces or relocates mechanical or electrical equipment, or when the building sits near a zone boundary or close to the BFE. Look for it in this order: the owner's closing documents, their flood insurance agent (policies in high-risk zones are often rated with one), the floodplain administrator's file, and only then a new survey. Reason: a tape measure cannot find a BFE. Without the certificate you know the height required and not the height you have. How to read one is its own procedure. See related: How to Read an Elevation Certificate.

7. Compute the gap and carry it into the quote. Subtract the existing equipment elevation from the DFE. That gap is the height the new equipment has to gain if the local rule reaches it. Write both the current-map gap and, where step 4 found one, the preliminary-map gap. Reason: the gap is the number that decides platform height, line-set length and whether the air handler moves, and it is the number the customer needs to see before choosing. What elevating or relocating involves is owned by its own card. See related: How to Elevate or Relocate Mechanical Equipment Above Flood Level.

8. Record the check on the job. Record the source, panel, effective date, zone, BFE with its datum, LOMC result, preliminary map result, the administrator's answers with the date of the call, and the certificate's figures. Reason: maps change and so do ordinances. A record lets the shop show what was true on the day it quoted.

A worked check

A customer on a tidal creek asks for a replacement heat pump; the existing condenser sits on a pad at grade beside the house. The office runs the check before the estimate visit and fills in the shop's record card. The panel number, dates and address below are illustrative.

FLOOD ZONE CHECK                       Checked: Mar 14
Address: 18 Creekside Lane
Source: FEMA Map Service Center, effective FIRM
Panel: 12345C0310J              Effective: Jun 2019
Zone at condenser: AE            BFE: 12 ft NAVD 88
LOMC on panel for parcel: none found
Preliminary FIRM: issued, BFE 13 ft, not yet effective
Freeboard (floodplain admin, by phone): 1 ft
  Applies to replacement equipment: yes, per ordinance
DFE, current map:      13.0 ft  (12 + 1)
DFE, preliminary map:  14.0 ft  (13 + 1)
Elevation certificate: owner's, 2016, datum NAVD 88
  Lowest machinery or equipment: 10.4 ft
Gap, current map:      2.6 ft   (13.0 - 10.4)
Gap, preliminary map:  3.6 ft   (14.0 - 10.4)

Reading the card. The condenser sits in an AE zone with a BFE of 12 feet. The community adds 1 foot, so the DFE on the current map is 13.0 feet. The administrator confirmed by phone that the ordinance applies its elevation rule to replacement equipment, so the replacement is caught even though it is not a substantial improvement. The owner's certificate puts the lowest machinery, the existing condenser, at 10.4 feet in the same datum, NAVD 88. The new unit has to gain 2.6 feet on the current map (13.0 minus 10.4).

The preliminary map. A new map with a BFE of 13 feet has been issued but is not yet effective. If it takes effect before the permit is issued, the DFE rises to 14.0 feet and the gap to 3.6 feet (14.0 minus 10.4). The administrator said permits are reviewed against the map in effect on the day of issue, so the estimate quotes the platform to the higher figure and says why on the estimate. A platform built to 13.0 feet would fall a foot short of the new map's requirement, which is an expensive foot to add later.

The datum check. The certificate is in NAVD 88 and so is the FIRM. Had the certificate been an older one in NGVD 29, the two figures could not be subtracted until one was converted, and the conversion is a location-specific number that a surveyor or the administrator supplies, not a constant.

What would have changed the quote. A LOMA covering the house would have taken the structure out of the zone on paper, but the condenser pad in the side yard might not be covered by it, so the letter's description would have to be read before relying on it. If the ordinance had applied freeboard only to new and substantially improved work, a like-for-like replacement at grade might have been allowed, and the elevated option would become a recommendation rather than a requirement; the quote would then offer both and say which the code requires. And if the zone had been shaded X, the federal elevation rule would not reach the equipment at all, though a customer on a tidal creek would still deserve to hear what the 0.2 percent line means for a unit sitting at grade.

Where this procedure stops

The lookup tells you the zone, the required height and the existing height. It does not decide whether the job is a substantial improvement, whether a variance is available, or how the change affects the customer's flood insurance rating. Those go to the floodplain administrator and the customer's insurance agent, and the shop walks in with the filled card.

References

• FEMA Flood Map Service Center and the National Flood Hazard Layer, for effective panels, Letters of Map Change and preliminary map data
• FEMA's Elevation Certificate form and its instructions
• 44 CFR 60.3, the National Flood Insurance Program floodplain management criteria a participating community's ordinance must at least meet
• See related: Flood Zones, Base Flood Elevation and Equipment; How to Elevate or Relocate Mechanical Equipment Above Flood Level
• See related: How to Read an Elevation Certificate; Reading the Place Before the Quote