Middlesex County and Waltham City property record for 18 Sioux Ave, Waltham, MA 02451
| Property Type | Single Family Home |
|---|---|
| Details | 3 bd · 1.5 ba · 1,550 sqft · built 1960 |
| Lot Size | 0.087 acres (3,798 sqft) |
| Owner | 2 Individual Names on File |
| Last Sale | $175,000 (Aug 1998) |
| Tax Bill | $5,458 (2026) |
| Flood Zone | Zone X (minimal risk) |
| APN | 125466 |
| Primary APN | 125466 |
|---|---|
| Alternative APN |
|
| Bedrooms | 3 Beds |
|---|---|
| Full Baths | 1.5 Baths |
| Half Baths | 1 Half Bath |
| Total Rooms | 5 Rooms |
| Stories | 1 Story |
| Building Area | 1,550 sqft Living Area |
| Gross Area | 1,840 sqft |
| Basement Area | 912 sqft |
| Unfinished Basement | 274 sqft |
| Year Built | Built 1960 |
|---|---|
| Effective Year Built | Effective 1960 |
| Architectural Style | Ranch |
| Exterior Material | Aluminum/Vinyl |
| Construction Type | Frame |
| Roof Type | Hip |
| Roof Material | Asphalt |
| Lot Area | 3,798 sqft (0.087 acres) |
| Garage Type | Detached |
| Cooling System | HVAC |
|---|---|
| Heating System | Forced Air with A/C |
| Heating Fuel | Gas |
| Account Number | 125466 |
|---|---|
| Street Address | 18 SIOUX AVE |
| City | WALTHAM |
| State | MA |
| Zip | 02451-3218 |
| Property Category | Residential |
| Property Type | Residential > Single Family > Home |
| Local Zoning Code | 1 |
| Legal Block | 3 |
| Legal Lot Number | 3 |
| Jurisdiction | WALTHAM MA |
| Township / Civil Division | WALTHAM |
| Census Block Group | 3 |
| Census Block | 3008 |
| Census Tract | 368101 |
18 Sioux Ave is owned and occupied by two individuals who bought it in August 1998.
Source: Middlesex County and Waltham City records, as of October 20, 2026
| Owner of Record | 2 Individual Names on File |
|---|---|
| Mailing Address | 18 SIOUX AVE, WALTHAM, MA 02451-3218 |
| Occupancy | Owner Occupied |
| Owner Type | Individual |
Owner names and exact recorded amounts are on file and can be viewed instantly on this page with a free 10-day trial.
| Deed Names | 2 Names on Deed |
|---|---|
| Last Sale | Aug 21, 1998 · Amount on File |
| Deed Sale | Aug 21, 1998 · Amount on File |
| Record Updated | Oct 29, 2026 |
The 2026 property tax bill for 18 Sioux Ave was $5,458, up 5.3% from the year before.
Source: Middlesex County and Waltham City assessment roll, as of April 14, 2026
| Type | Name |
|---|---|
| State | Massachusetts |
| County | Middlesex County |
| Municipality | Waltham City |
| Unified School District | Waltham School District (PK - 12) |
| Year | Tax Bill | Assessed Value | Assessed Market Value |
|---|---|---|---|
| 2026 | $5,458.00 (+5.29%) | $528,900 (+0.19%) Land $342,100 Building $186,800 | $616,476 (-7.85%) |
| 2025 | $5,184.00 (+5.56%) | $527,900 (+3.63%) Land $326,500 Building $201,400 | $668,990 (+11.32%) |
| 2024 | $4,911.00 (+0.59%) | $509,400 (+7.67%) Land $311,000 Building $198,400 | $600,970 |
| 2023 | $4,882.00 | $473,100 Land $283,900 Building $189,200 |
Assessed value and assessed market value are set for property tax purposes and are not market price estimates.
FEMA maps place 18 Sioux Ave in Zone X, an area of minimal flood risk, within 500 ft of a high-risk flood zone.
Source: FEMA National Flood Hazard Layer, effective September 10, 2026 · OpenFEMA NFIP redacted claims and policies, as of September 2026
| FEMA Flood Zone | Zone X minimal risk |
|---|---|
| Nearest Special Flood Hazard Area | Zone AE, within 500 ft |
| Flood Insurance Requirement | Not required lenders may require it |
| Flood Insurance Cost | Premium on File median of 15 individual policies |
| Nearby Flood Policies | 17 units insured incl. 2 condo units |
| Nearby Flood Claims | 35 (1978–2014) |
| Claims Outside the SFHA | 9 of 35 |
| Most Recent Claim | Dec 2014 · other causes |
| Claims by Event |
|
Values are read at the parcel center point; flood claims are located to the census block group, not this parcel; lenders make the official flood determination.
Wildfire risk around 18 Sioux Ave is low, with less than a 0.01% annual chance of wildfire.
Source: USDA Forest Service Wildfire Risk to Communities (2nd edition), as of 2024
| Wildfire Risk | Low lower than 99.1% of the US · lower than 98.7% of Massachusetts |
|---|---|
| Wildfire Likelihood | Under 0.01% annual chance |
| Exposure | None beyond ember reach |
Values cover an area roughly 900 ft across, not the parcel itself; insurers use their own ratings.
Source: EPA Safe Drinking Water Information System, as of September 2026
| Water System | WALTHAM WATER DEPARTMENT serves 65,218 people · EPA ID MA3308000 |
|---|---|
| Water Source | Purchased surface water from MWRA |
| Last State Inspection | Jun 2024 |
| Lead | 2 ppb (2025) action level 15 ppb |
| Water Quality | None last 10 years |
|---|---|
| Treatment and Procedure | None last 10 years |
| Monitoring and Reporting | 1 last 3 years |
Results are for the whole water system, not water tested at this address; lead at the tap also depends on the building's own pipes.
Source: FCC Broadband Data Collection, based on 664 locations within half a mile, as of December 31, 2025
| Provider | Max Down / Up (Mbps) |
|---|---|
| Verizon Fiber · Fixed Wireless in parts of the area | 2,300 / 2,300 |
| Xfinity Cable | 2,000 / 2,000 |
| Astound Broadband Cable | 1,500 / 50 |
| AT&T Fixed Wireless | 100 / 20 |
May also be available: T-Mobile.
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