How Many ADU Bids Should You Get Before Choosing a ...

How Many Bids Do You Really Need for Your ADU Project?

One of the first decisions you will face when planning your ADU project is how many contractor bids to collect before making a hiring decision. Get too few bids, and you may overpay or miss out on a better contractor. Get too many, and you will waste weeks collecting and comparing proposals while your project sits in limbo.

The short answer is that most homeowners should collect between three and five bids for their ADU project. But the right number depends on several factors, including your project complexity, timeline, budget, and the availability of qualified contractors in your area. In this guide, we will break down exactly how many bids to get, how to find quality contractors, and how to compare bids like a professional.

The Ideal Number of ADU Bids: 3 to 5

Industry experts, consumer protection organizations, and the California Contractors State License Board (CSLB) consistently recommend obtaining at least three bids for any significant construction project. For ADU projects specifically, we recommend expanding that range to three to five bids. Here is why.

Why Three Bids Is the Minimum

With fewer than three bids, you simply do not have enough data points to determine whether a price is fair. Two bids might differ by $50,000 or more, and without a third data point, you have no way of knowing which is more reasonable. Three bids give you a baseline for comparison and help identify outliers.

Why Five Bids Is Usually the Maximum

Collecting more than five bids introduces diminishing returns. Each additional bid requires time to schedule site visits, review proposals, and follow up with contractors. Beyond five bids, the additional information rarely justifies the time investment. In fact, too many bids can lead to analysis paralysis, where you become so overwhelmed by options that you delay making a decision.

Where to Find Qualified ADU Contractors for Bids

The quality of your bids depends entirely on the quality of the contractors you invite to bid. Here are the best sources for finding qualified ADU contractors in California.

CSLB Contractor Search

Start with the CSLB license lookup tool to verify that any contractor you are considering is properly licensed. For ADU projects, you typically need a contractor with a Class B (General Building) license. Some specialized work may require additional licenses, such as C-10 (Electrical) or C-36 (Plumbing).

Referrals from Friends and Family

Personal referrals remain the most reliable source for finding quality contractors. If someone you trust has built an ADU and had a positive experience, that referral is worth more than any online review. Ask for specifics about the contractor's communication, timeline adherence, and final quality.

Online Platforms

Websites like Houzz, Thumbtack, and BuildZoom can connect you with ADU contractors in your area. Be cautious with lead-generation sites that sell your information to multiple contractors, as this can result in aggressive sales tactics. For a deeper look at evaluating contractors you find online, check out our guide on evaluating contractor portfolios.

Local ADU Companies

Companies that specialize exclusively in ADU construction often provide the most streamlined experience. These firms understand the unique requirements of ADU projects and typically handle everything from design and permitting to construction and final inspection.

How to Run an Effective Bid Process

Getting multiple bids is only useful if you manage the process correctly. A disorganized bid process can lead to apples-to-oranges comparisons and poor decision-making.

Step 1: Define Your Project Scope

Before inviting contractors to bid, you need a clear project scope. At minimum, you should have architectural plans or at least a detailed description of what you want to build. The more specific your scope, the more accurate and comparable the bids will be.

Key scope elements to define include:

• ADU type (detached, attached, garage conversion, JADU)
• Square footage
• Number of bedrooms and bathrooms
• Finish level (standard, mid-range, high-end)
• Special features (solar panels, EV charging, smart home systems)
• Site conditions (slope, access, soil type)
• Utility connections needed

Step 2: Create a Bid Package

Prepare a standardized bid package that you give to every contractor. This ensures everyone is bidding on the same scope of work. Your bid package should include your architectural plans (if available), a written scope of work, your timeline expectations, your budget range (optional but helpful), and any specific material preferences.

Step 3: Schedule Site Visits

Every contractor should visit your property before submitting a bid. Site conditions can significantly impact costs, and a contractor who bids without seeing your property is likely to surprise you with change orders later. Schedule site visits within the same week if possible so the process does not drag out.

Step 4: Set a Bid Deadline

Give contractors a reasonable deadline of two to three weeks to submit their bids. This creates urgency while still allowing time for thorough estimating. Be clear that late bids will not be considered.

Step 5: Compare Bids Systematically

Once you have all bids in hand, compare them using a structured approach. We cover this in detail in our guide on how to read and compare ADU construction bids.

Understanding Price Variation Between ADU Bids

It is completely normal for ADU bids to vary by 20% to 40% or more. A $200,000 project might receive bids ranging from $170,000 to $280,000. Understanding why bids vary so much will help you evaluate them more effectively.

Common Reasons for Price Differences

The Danger of Choosing the Lowest Bid

While it is tempting to go with the cheapest option, the lowest bid often leads to the highest final cost. Low-ball bids frequently result in excessive change orders, corner-cutting on materials, substandard workmanship, and delays caused by underfunded subcontractors. The CSLB warns that unusually low bids are one of the most common indicators of contractor fraud.

How to Negotiate After Receiving Bids

Once you have collected your bids, negotiation is both expected and appropriate. Here is how to negotiate effectively without damaging your relationship with the contractor you ultimately choose.

Negotiation Best Practices

• Be transparent about your budget: Sharing your budget range (if reasonable) allows contractors to suggest value-engineering options that keep you within your means.
• Ask about value engineering: This is the process of finding less expensive alternatives that achieve the same result. For example, using engineered quartz instead of natural stone countertops can save $2,000 to $5,000 without sacrificing quality.
• Never reveal other contractors' prices: Sharing specific bid amounts is considered unprofessional and can backfire. Instead, tell the contractor that their bid is higher than others and ask if there are areas where costs could be reduced.
• Negotiate scope, not just price: Sometimes it is better to adjust the scope of work rather than asking for a blanket price reduction. Reducing scope maintains the contractor's profit margin, which means they are less likely to cut corners.

How Long Should the Bidding Process Take?

A well-managed ADU bidding process should take four to six weeks from start to finish. Here is a realistic timeline:

Do not rush this process. A few extra weeks spent collecting and comparing quality bids can save you tens of thousands of dollars and months of headaches during construction.

Special Cases: When to Adjust the Number of Bids

Simple Garage Conversion (2 to 3 Bids)

For straightforward garage conversions with no structural changes, two to three bids may be sufficient. These projects have a more predictable scope, which makes bid comparison easier.

Complex Custom ADU (4 to 5 Bids)

For custom detached ADUs with unique design features, challenging site conditions, or budgets over $300,000, collect four to five bids. The complexity of these projects means there will be more variation between bids, and having more data points helps you make a better decision.

Rural or Limited Market Areas (3 Bids)

In areas with fewer ADU contractors, three bids may be the most you can reasonably obtain. In some rural California counties, you may struggle to find even three qualified ADU builders. In this case, consider expanding your search radius to include contractors from neighboring cities or counties.

Frequently Asked Questions About ADU Bids

Is it appropriate to share one contractor's bid with another contractor?

No. Sharing specific bid details from one contractor with another is considered unprofessional and can damage your credibility. You can tell a contractor that their bid is higher than others without revealing specific numbers. This approach maintains trust while still creating competitive pressure.

Should I accept a bid that is significantly lower than the others?

Be very cautious with bids that are 20% or more below the average. While the contractor may genuinely be more efficient, abnormally low bids often indicate that the contractor has missed important scope items, plans to use inferior materials, or intends to make up the difference through change orders. Ask the contractor to explain specifically why their bid is lower before making a decision.

How long should a bid remain valid?

Most ADU contractor bids are valid for 30 to 60 days. Material prices and labor availability change frequently, so bids older than 60 days may no longer reflect current market conditions. If you need more time to make a decision, ask the contractor if they will extend the bid validity period.

Can I negotiate after accepting a bid?

Once you accept a bid and sign a contract, the terms are generally fixed. However, changes in scope (through change orders) are common during construction. For information on managing change orders, see our guide on handling change orders without budget blowups.

What if all the bids are higher than my budget?

If all bids exceed your budget, you have several options. You can reduce the project scope (smaller ADU, fewer custom features), adjust your finish level (standard instead of premium), explore ADU financing options to increase your budget, or wait for market conditions to improve. Do not ask contractors to match an unrealistic budget, as this usually results in corner-cutting and disputes during construction.

Should I require contractors to include a breakdown in their bid?

Absolutely. A detailed line-item breakdown is essential for comparing bids accurately. Without a breakdown, you cannot determine whether a lower bid reflects lower prices, a smaller scope, or inferior materials. Insist on itemized bids that separate costs for site work, foundation, framing, electrical, plumbing, HVAC, finishes, and permits.

Ready to start collecting bids for your ADU project? Our team can connect you with pre-vetted ADU contractors in your area.

Frequently Asked Questions About the ADU Bidding Process

Is it worth getting more than five bids for my ADU project?

In most cases, getting more than five bids provides diminishing returns. After reviewing five detailed proposals, you will have a clear understanding of the market rate for your project, the typical scope of work, and the range of material options available. Additional bids beyond five tend to repeat the same information and can actually delay your decision-making process. However, if your project involves unusual design features, specialized construction methods, or a very tight budget, a sixth or seventh bid may provide useful alternatives. Focus on quality over quantity by ensuring each contractor you invite to bid is licensed, experienced with ADUs, and has strong references.

What should I provide to contractors to get accurate ADU bids?

To receive the most accurate and comparable bids, provide each contractor with the same set of project documents. This includes your architectural plans and engineering drawings, a clear description of your desired finishes and materials, your target budget range, your preferred timeline, any specific requirements from your city's planning department, and access to the build site for measurements. The more information you provide upfront, the more accurate the bids will be and the fewer change orders you will face during construction. For guidance on the details that should appear in your final agreement, see our article on what an ADU contract should include.

How do I compare ADU bids fairly when each contractor formats them differently?

Create a standardized comparison spreadsheet with consistent categories that you apply to every bid. Common categories include site preparation, foundation, framing, electrical, plumbing, HVAC, roofing, insulation, drywall, flooring, cabinetry, fixtures, painting, exterior finishes, landscaping, permits and fees, and general conditions. Map each contractor's line items into your spreadsheet to identify gaps or items that were included by some contractors but not others. This approach transforms apples-to-oranges bids into an apples-to-apples comparison that makes decision-making much clearer.

Can I negotiate the price after receiving an ADU bid?

Yes, and most contractors expect some negotiation. Start by asking questions about specific line items that seem higher than comparable bids. Contractors are often willing to adjust pricing on materials by suggesting alternative brands or grades, reduce their markup percentage for larger projects, offer payment schedule adjustments that reduce their financing costs, or bundle additional work at a reduced rate. Be respectful and transparent in your negotiations. Sharing that you have received other bids and are comparing options is appropriate, but avoid revealing specific competitors' pricing. Read our guide on handling change orders without budget blowups for more cost management strategies.