ADU Construction Planning in Pasadena, California

This page supports project planning and a possible company referral. It is not the City of Pasadena, a lender, designer or builder. It cannot decide whether an ADU is allowed at an address.

Start with current City guidance

Pasadena’s live ADU page lists Ordinance 7420 and rules in effect since May 20, 2024. California building codes changed again on January 1, 2026. That change affects the City’s older standard plans.

Use the live City pages, not an undated plan image or a company’s old summary. Also distinguish City of Pasadena property from an unincorporated area or a neighbouring city with a Pasadena postal address.

Use the virtual consultation appropriately

The City offers an online ADU meeting for early zoning feedback before plan check. It can help find questions early. It is not a building permit and does not replace full plans and site details.

Prepare the address, current buildings and unit count. Add the ADU type, rough location and size. Include parking or conversion facts and exact questions. Record the date and any records the City requests. If the design changes, check those facts again.

Do not assume older standard plans remain generally available

Pasadena’s Standard Plans Program says general use of its old catalog ended after December 31, 2025. The City links that change to state building codes that began on January 1, 2026.

The City says those plans now have a narrow use. They are limited to homes red-tagged because of the Eaton Fire while the City reviews new plans. This is not a general right to use the old catalog.

Before using any Pasadena standard plan, confirm the facts below.

• whether the property qualifies under the current program;
• the specific plan and code edition;
• what site-specific design and engineering remains;
• whether planned modifications retain status; and
• who is responsible for corrections and permit planning.

If the property does not qualify, compare a current custom or other accepted design path on total cost and fit.

Historic context can affect design

The City’s current ADU material lists added visibility checks in historic areas. Confirm historic status early. The location, height, size, outside finish and view from the street may affect a simple standard plan.

Do not treat “State-law ADU” as meaning that historic details can be ignored. Ask the City which current standards and review steps apply to the exact property.

Distinguish the City loan program from ordinary project financing

Pasadena announced a Second Unit ADU Program with loans up to $225,000 at 1% simple interest for some owners. The program has rules for the owner, property, rent and tenants.

It is not a low-cost loan for every ADU. Check current funds and all legal and occupancy rules with the program. Do this before putting the loan in a budget. A builder should not claim that an owner qualifies.

Create a property-specific scope

A Pasadena site brief should confirm the permit office, lot and current units. Add standard-plan rules, historic status, site size, access, slope and drainage. Record power, water, sewer, fire, parking and garage facts. State the planned use.

Then choose one of the project routes below.

• detached new construction;
• attached addition;
• garage or other existing-space conversion;
• junior ADU where applicable; or
• a broader property strategy that needs professional advice.

Each route needs a different design, structural and utility assumption. Do not compare them only by unit size.

Compare Pasadena companies fairly

Ask for proof of recent Pasadena ADU work by the same legal business. This matters even more for a historic or unusual site. Ask who provides the building plans, engineering and energy forms. Add permit replies and utility planning.

Every quote should state the items below.

• the dated plan set and site assumptions;
• consultant and agency inclusions;
• demolition and access work;
• foundation and drainage basis;
• electrical, water and sewer work;
• finish specifications and allowances;
• exclusions and owner work;
• schedule dependencies; and
• change-order and payment terms.

Verify the contracting entity through CSLB. A referral or a City program listing does not replace that check.

Cost and timeline

Use the 2026 Los Angeles ADU cost guide only as a broad budgeting framework. Pasadena-specific consultation, design, historic context, utility work, access and finish choices must be added as actual work.

The timeline should start with site checks, not the first day of building. Include plan choice, design, engineering, City review and fixes. Add utility work, orders, the build, inspections and final approval. If a company uses an older standard plan, stop and check program rules before accepting the schedule.

Independent referral position

Company availability in Pasadena is not guaranteed. If this site introduces a company, the company controls its own review, quote, contract and work. The owner should independently verify credentials, insurance, references and every work item.

Preserve the current-plan evidence

If a quote uses a standard plan or City program, save the live rules page. Record the date, plan number and code year. Ask why the property qualifies and which site sheets are still needed. A catalog image or old download is not enough.

If the program changes during design, ask the City or designer for the next step in writing. Record whether new review or a new plan changes ownership, fees or time. This makes quotes easier to compare and reduces trust in sales claims.

Plan the owner choice calendar

Set choice dates for the layout, outside materials, windows and equipment. Add cabinets, fixtures and appliances. Match those dates to the permit filing and items that take time to order. A late choice can change a standard detail or cause another review.

Move from Pasadena research to comparison

Check the address against the Los Angeles County city or county paths, then record parcel and program findings in the early site-check guide. When the design basis is stable, use the ADU builder comparison to reconcile consultant work, utilities, allowances and evidence across quotes.