Mandatory Housing Affordability (MHA) Program

 See also: Incentive Zoning Program

What Is It?

Mandatory Housing Affordability (MHA) is a developer contribution. Developer contributions are either a payment or provided benefit in consideration of a proposed project. The City of Seattle requires MHA developer contributions to mitigate the impacts of new development.

To achieve the goal of providing affordable housing in Seattle, development subject to the MHA requirements must contribute to affordable housing as part of most commercial, residential, or live-work projects. This contribution can be provided by including affordable housing units within new development (performance option) or paying into a fund that will support the development of affordable housing (payment option).

A property is subject to the MHA requirements after the City Council approves a City-initiated rezone (legislative) or an applicant-initiated rezone (quasi-judicial) that increases the maximum height or floor area ratio (FAR), or establishes a different zoning designation. The MHA requirements are found in the standards of the zone for legislative rezones, and as part of the Property Use and Development Agreements (PUDA) associated with quasi-judicial rezones (i.e. contract rezones). Most rezoned areas will have an MHA suffix, (M), (M1), (M2) to determine the appropriate MHA payment or performance amount; however, there are some zones where MHA is effective without an MHA suffix.

You can choose to comply with the MHA requirements through the payment option or the performance option.

  • The payment option allows you to make a payment to the City as part of the permitting process which will be used for future affordable housing development.
  • The performance option allows you to incorporate affordable units into the proposed development.

Where required, we expect you to document your developer contributions on the plans before we issue a Master Use Permit (MUP) or building permit. Before we issue a building permit, you may also need to provide recorded agreements and declarations to document the ongoing terms of your contribution(s), as well as make any payments.

Relationship with Incentive Zoning (IZ)

When a project is subject to both MHA and Incentive Zoning (IZ), the MHA program requirements satisfy the affordable housing requirement for the IZ program. Required developer contributions to child care, open space amenities, Transferable Development Potential and Rights (TDP/TDR) and Regional Development Credits (RDC) must still be provided via the IZ program.

Read the Code

Read the Seattle Municipal Code (SMC) section MHA provisions, SMC 23.58B and SMC 23.58C.

CPI Mandatory Housing Affordability Payment Adjustments

Please note the Land Use Code (SMC 23.58B.040 and 23.58C.040, respectively), requires the payment calculation amounts to be adjusted annually. The commercial and residential / live-work MHA requirements direct us to use the Consumer Price Index (CPI) to make these adjustments on March 1 of each year in proportion to the annual change for the previous calendar year in the CPI. The payment calculation amounts for your project depend on the date your project vested to the Land Use Code (SMC 23.76.026). You may need to know the zone, MHA suffix, and MHA payment and performance area (see Map A for SMC 23.58B.050 or 23.58C.050), or a combination of these to determine the correct payment calculation amount.

The tables below show the CPI adjusted amounts from the initial dollar amounts adopted in the code to present.  

*Due to code changes effective April 19, 2019, the payment calculation amount may be different for your project. Please see your Zoning reviewer for more information.**  

Table 1: Adjusted Payment Calculation Amounts for Chapter 23.58B - Commercial Requirements in Downtown, SM-SLU, and SM-U Zones

In Downtown, SM- SLU, and SM-U Zones Effective Date of payment amount per 23.58B.040.A.2 Initial payment calculation amount per code 12/17/15 - 2/29/16 Adjusted payment calculation amount 3/1/16 - 2/28/17 Adjusted payment calculation amount 3/1/17 - 2/28/18 Adjusted payment calculation amount 3/1/18 - 2/28/19 Adjusted payment calculation amount 3/1/19 - 2/29/20 Adjusted payment calculation amount 3/1/20 - 2/28/21 Adjusted payment calculation amount 3/1/21 - 2/28/22 Adjusted payment calculation amount 3/1/22 -2/28/23
DH1/45 N/A N/A N/A N/A N/A N/A N/A N/A
DH2/55 N/A N/A N/A N/A N/A N/A N/A N/A
DH2/75 $15.00 $15.33 $15.72 $16.27 $16.73 $17.33 $17.76  $18.29
DH2/85 N/A N/A N/A N/A N/A N/A N/A N/A
DMC-75 $8.25 $8.43 $8.65 $8.95 $9.20 $9.53 $9.77 $10.06
DMC-95 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
DMC 85/75-170 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
DMC-145 $10.00 $10.22 $10.48 $10.85 $11.15 $11.55 $11.84 $12.19
DMC-170 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
DMC 240/290-440 $10.00 $10.22 $10.48 $10.85 $11.15 $11.55 $11.84 $12.19
DMC 340/290-440 $12.50 $12.77 $13.10 $13.56 $13.94 $14.44 $14.80 $15.24
DOC1 U/450-U $14.75 $15.07 $15.46 $16.00 $16.45 $17.04 $17.47 $17.99
DOC2 500/300-550 $14.25 $14.56 $14.93 $15.46 $15.89 $16.47 $16.88 $17.38
DRC 85-170 $13.50 $13.79 $14.15 $14.65 $15.06 $15.60 $15.99 $16.46
DMR/C 75/75-95 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
DMR/C 75/75-170 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
DMR/C 95/75 $17.50 $17.88 $18.34 $18.99 $19.52 $20.22 $20.72 $21.34
DMR/C 145/75 $17.50 $17.88 $18.34 $18.99 $19.52 $20.22 $20.72 $21.34
DMR/C 280/125 $14.25 $14.56 $14.93 $15.46 $15.89 $16.47 $16.88 $17.38
DMR/R 95/65 $14.00 $14.30 $14.67 $15.19 $15.61 $16.18 $16.58 $17.07
DMR/R 145/65 $16.00 $16.35 $16.77 $17.36 $17.84 $18.49 $18.95 $19.51
DMR/R 280/65 $16.00 $16.35 $16.77 $17.36 $17.84 $18.49 $18.95 $19.51
IDM 65-150* N/A N/A N/A N/A N/A N/A N/A N/A
IDM 75-85* N/A N/A N/A N/A N/A N/A N/A N/A
IDM 85/85-170* $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
IDM 165/85-170* $20.75 $21.20 $21.75 $22.51 $23.14 $23.98 $24.57 $25.30
IDR 45/125-270 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
IDR 170 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
IDR/C 125/150-270 $20.75 $21.20 $21.75 $22.51 $23.14 $23.98 $24.57 $25.30
PMM-85 N/A N/A N/A N/A N/A N/A N/A N/A
All PSM zones N/A N/A N/A N/A N/A N/A N/A N/A
SM-SLU 100/65-145 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76  
SM-SLU 85/65-160 N/A N/A N/A N/A N/A N/A N/A N/A
SM-SLU 85-280* $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
SM-SLU 175/85-280 $11.25 $11.49 $11.79 $12.20 $12.55 $13.00 $13.32 $13.72
SM-SLU 240/125-440 $10.00 $10.22 $10.48 $10.85 $11.15 $11.55 $11.84 $12.19
SM-SLU/R 65/95 $8.25 $8.43 $8.65 $8.95 $9.20 $9.53 $9.77 $10.06
SM-SLU 100/95 $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
SM-SLU 145 $9.25 $9.45 $9.69 $10.04 $10.32 $10.69 $10.95 $11.28
SM-U 85 $7.00 $7.15 $7.34 $7.59 $7.81 $8.09 $8.29 $8.54
SM-U/R 75-240 $20.00 $20.44 $20.96 $21.70 $22.31 $23.11 $23.68 $24.39
SM-U 75-240 $20.00 $20.44 $20.96 $21.70 $22.31 $23.11 $23.68 $24.39
SM-U 95-320 $20.00 $20.44 $20.96 $21.70 $22.31 $23.11 $23.68 $24.39

Table 2 - Adjusted Payment Calculation Amounts for Chapter 23.58B - Commercial Requirements OUTSIDE Downtown, SM-SLU, and SM-U Zones

OUTSIDE Downtown, SM-SLU, and SM-U Zones Effective date of payment amount   per 23.58B.040.A.2 Initial payment calculation amount per code 12/17/15 - 2/29/16 Adjusted payment calculation amount 3/1/16 - 2/28/17 Adjusted payment calculation amount 3/1/17 - 2/28/18 Adjusted payment calculation amount 3/1/18 - 2/28/19 Adjusted payment calculation amount 3/1/19 - 2/29/20 Adjusted payment calculation amount 3/1/20 - 2/28/21 Adjusted payment calculation amount 3/1/21 - 2/28/22 Adjusted payment calculation amount 3/1/22 -2/28/23
LOW AREAS                
All Industrial Buffer zones (IB) N/A N/A N/A N/A N/A N/A N/A N/A
All Industrial General zones (IG) N/A N/A N/A N/A N/A N/A N/A N/A
All Master Planned Communities-Yesler Terrace zones (MPC-YT) N/A N/A N/A N/A N/A N/A N/A N/A
IC 85-175 $10.00 $10.22 $10.48 $10.85 $11.15 $11.55 $11.84 $12.19
Zones with an (M) suffix $5.00 $5.11 $5.24 $5.42 $5.58 $5.78 $5.92 $6.10
Zones with an (M1) suffix $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
Zones with an (M2) suffix $9.00 $9.20 $9.43 $9.76 $10.04 $10.40 $10.66 $10.97
Other zones where provisions refer to Chapter 23.58B $5.00 $5.11 $5.24 $5.42 $5.58 $5.78 $5.92 $6.10
MEDIUM AREAS                
All Industrial Buffer zones (IB) N/A N/A N/A N/A N/A N/A N/A N/A
All Industrial General zones (IG) N/A N/A N/A N/A N/A N/A N/A N/A
All Master Planned Communities-Yesler Terrace zones (MPC-YT) N/A N/A N/A N/A N/A N/A N/A N/A
IC 85-160 $10.00 $10.22 $10.48 $10.85 $11.15 $11.55 $11.84 $12.19
Zones with an (M) suffix $7.00 $7.15 $7.34 $7.59 $7.81 $8.09 $8.29 $8.54
Zones with an (M1) suffix $11.25 $11.49 $11.79 $12.20 $12.55 $13.00 $13.32 $13.72
Zones with an (M2) suffix $12.50 $12.77 $13.10 $13.56 $13.94 $14.44 $14.80 $15.24
Other zones where provisions refer to Chapter 23.58B $7.00 $7.15 $7.34 $7.59 $7.81 $8.09 $8.29 $8.54
HIGH AREAS                
All Industrial Buffer zones (IB) N/A N/A N/A N/A N/A N/A N/A N/A
All Industrial General zones (IG) N/A N/A N/A N/A N/A N/A N/A N/A
All Master Planned Communities- Yesler Terrace zones (MPC-YT) N/A N/A N/A N/A N/A N/A N/A N/A
IC 85-160 $10.00 $10.22 $10.48 $10.85 $11.15 $11.55 $11.84 $12.19
Zones with an (M) suffix $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76
Zones with an (M1) suffix $12.75 $13.03 $13.36 $13.83 $14.22 $14.73 $15.10 $15.55
Zones with an (M2) suffix $14.50 $14.82 $15.20 $15.73 $16.17 $16.75 $17.17 $17.68
Other zones where provisions refer to Chapter 23.58B $8.00 $8.17 $8.38 $8.68 $8.92 $9.24 $9.47 $9.76

Table 3 - Adjusted Payment Calculation Amounts for Chapter 23.58C - Residential and Live-Work Requirements in Downtown, SM-SLU, and SM-U 85 Zones

In Downtown, SM-SLU, and SM-U 85 Zones Effective Date of Payment Amount per 23.58C.040.A.2 Initial payment calculation amount per code 9/16/16 - 2/28/17 Adjusted payment calculation amount 3/1/17 - 2/28/18 Adjusted payment calculation amount 3/1/18 - 2/28/19 Adjusted payment calculation amount 3/1/19 - 2/29/20 Adjusted payment calculation amount 3/1/20 - 2/28/21 Adjusted payment calculation amount 3/1/21 - 2/28/22 Adjusted payment calculation amount 3/1/22 - 2/28/23
DH1/45 N/A N/A N/A N/A N/A N/A N/A
DH2/55 N/A N/A N/A N/A N/A N/A N/A
DH2/75 $12.75 $13.08 $13.54 $13.92 $14.42 $14.78 $15.22  
DH2/85 N/A N/A N/A N/A N/A N/A N/A
DMC-75 $12.75 $13.08 $13.54 $13.92 $14.42 $14.78 $15.22
DMC-95 $12.75 $13.08 $13.54 $13.92 $14.42 $14.78 $15.22
DMC 85/75-170 $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
DMC-145 $13.00 $13.33 $13.80 $14.19 $14.70 $15.07 $15.51
DMC-170 $5.50 $5.64 $5.84 $6.00 $6.22 $6.37 $6.56
DMC 240/290-440 $8.25 $8.46 $8.76 $9.00 $9.33 $9.56 $9.85
DMC 340/290-440 $8.25 $8.46 $8.76 $9.00 $9.33 $9.56 $9.85
DOC1 U/450-U $12.00 $12.31 $12.74 $13.10 $13.57 $13.91 $14.32
DOC2 500/300-550 $10.25 $10.51 $10.88 $11.19 $11.59 $11.88 $12.23
DRC 85-170 $10.00 $10.26 $10.62 $10.91 $11.31 $11.59 $11.93
DMR/C 75/75-95 $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
DMR/C 75/75-170 $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
DMR/C 95/75 $12.75 $13.08 $13.54 $13.92 $14.42 $14.78 $15.22
DMR/C 145/75 $11.75 $12.05 $12.48 $12.83 $13.29 $13.62 $14.02
DMR/C 280/125 $13.00 $13.33 $13.80 $14.19 $14.70 $15.07 $15.51
DMR/R 95/65 $12.75 $13.08 $13.54 $13.92 $14.42 $14.78 $15.22
DMR/R 145/65 $11.75 $12.05 $12.48 $12.83 $13.29 $13.62 $14.02
DMR/R 280/65 $13.00 $13.33 $13.80 $14.19 $14.70 $15.07 $15.51
IDM 65-150 N/A N/A N/A N/A N/A N/A N/A
IDM 75-85 N/A N/A N/A N/A N/A N/A N/A
IDM 85/85-170 $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
IDM 164/85-170 $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
All IDR and IDR/C zones* $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
PMM-85 N/A N/A N/A N/A N/A N/A N/A
All PSM zones N/A N/A N/A N/A N/A N/A N/A
SM-SLU 100/65-145 $7.75 $7.95 $8.23 $8.46 $8.76 $8.98 $9.25
SM-SLU 85/65-160 N/A N/A N/A N/A N/A N/A N/A
SM-SLU 85-280 $10.00 $10.26 $10.62 $10.91 $11.31 $11.59 $11.93
SM-SLU 175/85-280 $10.00 $10.26 $10.62 $10.91 $11.31 $11.59 $11.93
SM-SLU 240/125-440 $10.00 $10.26 $10.62 $10.91 $11.31 $11.59 $11.93
SM-SLU/R 65/95 $12.75 $13.08 $13.54 $13.92 $14.42 $14.78 $15.22
SM-SLU 100/95 $7.50 $7.69 $7.96 $8.19 $8.48 $8.69 $8.95
SM-SLU 145 $7.75 $7.95 $8.23 $8.46 $8.76 $8.98 $9.25
SM-U 85 $13.25 $13.59 $14.07 $14.46 $14.98 $15.36 $15.81

Table 4 - Adjusted Payment Calculation Amounts for Chapter 23.58C - Residential and Live-Work Requirements OUTSIDE Downtown, SM-SLU, and SM-U 85 Zones

OUTSIDE Downtown, SM-SLU, and SM-U 85 Zones Effective date of payment per 23.58C.040.A.2 Initial payment calculation amount per code 9/16/2016 -2/28/17 Adjusted payment calculation amount 3/1/17 -2/28/18 Adjusted payment calculation amount 3/1/18 -2/28/19 Adjusted payment calculation amount 3/1/19 -2/29/20 Underline effective 4/19/19 - 2/29/20 Adjusted payment calculation amount 3/1/20-2/28/21

Adjusted payment calculation amount       3/1/21-2/28/22  

Adjusted payment calculation amount 3/1/22 -2/28/23
LOW AREAS              
Zones with an (M) suffix See Director's Rule 14-2016 See Director's Rule 14-2016 See Director's Rule 14-2016 $7.64 $7.92 $8.11 $8.35      
Zones with an (M1) suffix See Director's Rule 14-2016 See Director's Rule 14-2016 See Director's Rule 14-2016 $12.28 $12.72 $13.04 $13.43      
Zones with an (M2) suffix See Director's Rule 14-2016 See Director's Rule 14-2016 See Director's Rule 14-2016 $13.64 $14.14 $14.49 $14.92      
MEDIUM AREAS        
Zones with an (M) suffix See Director's Rule 14-2016 See Director's Rule 14-2016 See Director's Rule 14-2016 $14.46 $14.98 $15.36 $15.81      
Zones with an (M1) suffix $20.00 $20.51 $21.24 $21.83 $22.62 $23.18 $23.87  
Zones with an (M2) suffix See DR 14-2016 See DR 14-2016 See DR 14-2016 $24.29 $25.16 $25.79 $26.55  
HIGH AREAS        
Zones with an (M) suffix $20.75 $21.28 $22.03 $22.65 $23.47 $24.05 $24.76
Zones with an (M1) suffix $29.75 $30.51 $31.59 $32.47 $33.64 $34.48 $35.50  
Zones with an (M2) suffix $32.75 $33.59 $34.77 $35.75 $37.04 $37.96 $39.08  

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