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Updated 2025 Tax Year

Middlesex County
Property Tax Guide

Everything you need to know about property taxes in Middlesex County, MA. Rates, due dates, exemptions, and how it affects your monthly payment.

7 Official Sources
8 min read
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Quick Facts
Tax Rate
$14.64 per $1,000 of assessed value (average residential rate)
1st Due
Aug 1
2nd Due
Nov 1
Exemptions
5+ Available
Section 1

How Property Tax Works

Property taxes in Middlesex County, Massachusetts, serve as the primary funding mechanism for essential local services including public education, municipal operations, public safety, and infrastructure maintenance. The county encompasses 54 cities and towns, each setting their own tax rates based on local budgetary needs and state regulations. Property taxes are administered at the municipal level, with each community's assessor determining property values and tax rates according to Massachusetts General Laws.

The effective property tax rates in Middlesex County typically range from approximately 0.8% to 1.5% of assessed value, though this varies significantly by municipality. For fiscal year 2025, residential properties face an average rate of $14.64 per $1,000 of assessed value, while commercial, industrial, and personal properties are taxed at $21.04 per $1,000. Massachusetts uses a full fair cash value assessment system with annual reassessments in most communities, ensuring property taxes reflect current market conditions.

Section 2

What Makes Up Your Tax Bill

ComponentRate (per $1,000)Description
Residential Base Rate$14.64Standard rate for single-family homes, condos, and residential properties
Commercial/Industrial Rate$21.04Rate applied to business properties, industrial facilities, and commercial real estate
Municipal Services LevyVariesPortion funding police, fire, public works, and general government operations
School District AssessmentVariesLargest component, typically 50-60% of total tax bill funding K-12 education
Debt ServiceVariesPayments on municipal bonds for infrastructure, school buildings, and capital projects
Special District AssessmentsVariesAdditional charges for water/sewer districts, lighting districts, or improvement areas
Section 3

When Are Property Taxes Due?

For the 2025/2026 tax year in Middlesex County, property taxes are due in two installments:

First Installment
Aug 1
Delinquent after Dec 10
Second Installment
Nov 1
Delinquent after Apr 10
Pro tip: If you pay through mortgage escrow, your lender splits these payments across your monthly mortgage. If you pay directly, set calendar reminders to avoid late penalties.
Section 4

Supplemental Tax Bills

Supplemental property taxes in Middlesex County are triggered by significant changes to property ownership or improvements that occur during the fiscal year. Common triggers include new construction completion, major renovations that add value, subdivision of land, or changes in property classification. When a Certificate of Occupancy is issued for new construction or substantial improvements, a supplemental assessment is calculated based on the difference between the original assessed value and the new enhanced value.

The supplemental tax calculation takes the difference between the old and new assessed values, multiplies by the applicable tax rate, and prorates the amount from the effective date of the change through June 30th (the end of the fiscal year). For example, if a $100,000 addition is completed on January 1st with a tax rate of $14.64 per $1,000, the supplemental tax would be: ($100,000 ÷ 1,000) × $14.64 × 0.5 (half year) = $732. This supplemental bill is issued separately from the regular annual tax bill and typically due within 30 days of issuance.

Example Calculation

$300,000 Home:

  • Assessed Value: $300,000
  • Less: Residential Exemption: $0 (varies by municipality)
  • Net Taxable Value: $300,000
  • Annual Tax: $300,000 ÷ 1,000 × $14.64 = $4,392
  • Monthly Escrow: $4,392 ÷ 12 = $366

$600,000 Home:

  • Assessed Value: $600,000
  • Less: Residential Exemption: $0 (varies by municipality)
  • Net Taxable Value: $600,000
  • Annual Tax: $600,000 ÷ 1,000 × $14.64 = $8,784
  • Monthly Escrow: $8,784 ÷ 12 = $732

$1,000,000 Home:

  • Assessed Value: $1,000,000
  • Less: Residential Exemption: $0 (varies by municipality)
  • Net Taxable Value: $1,000,000
  • Annual Tax: $1,000,000 ÷ 1,000 × $14.64 = $14,640
  • Monthly Escrow: $14,640 ÷ 12 = $1,220

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Section 5

Escrow & Property Taxes

Most mortgage lenders in Middlesex County require borrowers to establish escrow accounts for property tax payments, particularly when the loan-to-value ratio exceeds 80%. The lender collects monthly payments equal to the annual tax bill divided by 12, plus a cushion typically equal to two months of payments. Property tax bills in Massachusetts are generally issued quarterly or semi-annually depending on the municipality, with common due dates being August 1st, November 1st, February 1st, and May 1st.

Lenders typically pay property taxes directly to the municipal collector before the due dates to avoid interest charges and potential liens. Homeowners should verify their escrow account annually when tax bills are issued, as assessment changes or rate adjustments may require escrow payment modifications. If property taxes increase significantly, lenders may require a lump sum payment to cover any escrow shortage or spread the shortage over 12 months in addition to the higher monthly payment. Borrowers without escrow accounts are responsible for making quarterly payments directly to their city or town collector's office.

How HonestCasa Helps
  • Understand whether your escrow is set correctly
  • See how rising taxes will change your monthly payment
  • Plan ahead instead of being surprised by "shortage" letters
Section 6

Frequently Asked Questions

Q: When are property taxes due in Middlesex County? A: Due dates vary by municipality but commonly fall on quarterly dates: August 1st, November 1st, February 1st, and May 1st. Some communities use semi-annual billing. Check with your local tax collector for specific dates.

Q: What exemptions are available for homeowners? A: Massachusetts offers various exemptions including residential exemptions (up to $3,000 in some communities), senior citizen exemptions, veteran exemptions, and disability exemptions. Contact your local assessor for specific eligibility requirements and applications.

Q: How can I appeal my property assessment? A: File an abatement application with your local board of assessors within 30 days of receiving your actual tax bill. The Massachusetts Department of Revenue provides forms and guidance at mass.gov.

Q: What happens if I pay my property taxes late? A: Interest charges accrue at 14% annually on overdue amounts. After a certain period, the municipality may place a tax lien on the property and eventually pursue foreclosure proceedings.

Q: Can I pay property taxes online? A: Most Middlesex County municipalities offer online payment options through their websites. Check your local collector's website or mass.gov for available payment methods.

Q: How often are properties reassessed? A: Most communities conduct annual assessments, though some may reassess every three years. The state requires communities to assess at full fair cash value.

Q: What if I disagree with a supplemental tax bill? A: You can appeal supplemental assessments using the same abatement process as regular assessments. File within 30 days of the supplemental bill date.

Q: Are solar panels subject to property tax? A: Massachusetts law provides a 20-year exemption for solar energy systems installed on residential properties, meaning the added value from solar panels is exempt from property taxation.

Verified Sources

Backed by 7 Official Government Sources

Every fact in this guide is sourced from official county, state, and federal documents.

01
County
Middlesex County Assessormass.gov
02
Tax Doc
Massachusetts Tax Ratesmass.gov
03
Tax Doc
Fiscal Year 2025 Tax Rates and Assessed Valuessudbury.ma.us
04
Tax Doc
Tax Rates by Classdls-gw.dor.state.ma.us
05
State
Real Estate | Natick, MA - Official Websitenatickma.gov
06
Assessors FAQ - Ashby, Mass.ci.ashby.ma.us
07
Tax Doc
atb 2012-15 commonwealth of massachusetts appellate tax ...archives.lib.state.ma.us
All sources verified as of 2025 Tax Year

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