California has a standard form for warning a buyer about a utility assessment, and it only works once there's an amount to put on it. On Tiburon's Mar West Street right now, there isn't one. The Town Council has advanced a proposed undergrounding district, hired an engineer and approved money for design. The property owners haven't voted, and nobody knows yet what any single parcel will owe. If you buy or sell a home there in the coming months, the transaction lands before that form has anything to say.
Where the Mar West district stands
On Sept. 16, the Tiburon Town Council voted 4-0 to move forward with an underground utility assessment district along Mar West Street, according to the Marin Independent Journal. The preliminary map covers 40 parcels. Most are on Mar West, and the rest are on Esperanza Street and Las Lomas Lane.
This is the first neighborhood to take a real step since the town ended its nearly eight-year moratorium on new districts in April 2025, as The Ark reported. In January, Mar West residents got the go-ahead to circulate petitions and raise a third of the money for the design reports. The September vote picked CSW Stuber-Stroeh Engineering of Novato to prepare the plans, cost estimates, allocation method and engineer's report. It also approved a $113,312 budget amendment to cover the other two-thirds. Bond funding pays that money back if the district forms. If it doesn't form, the town absorbs the loss.
Here's what still has to happen, based on the town's Utility Undergrounding District Policy:
- The engineer finishes the report and assigns each parcel its share of the cost.
- Owners receive a Notice of Proposed Assessments.
- At least 45 days after that mailing, the council holds a public hearing and the Town Clerk counts the ballots.
- If the vote approves it, the council confirms the assessments and records the lien.
- Owners get at least 30 days to pay in cash before the remaining amount is bonded.
The policy estimates that the full process takes at least 12 to 24 months if there are no legal challenges. Mar West is near the start of that window.
The vote counts dollars, and a no vote doesn't get you out
Many buyers assume one home gets one vote. Tiburon's policy says ballots are "weighted on dollars assessed," so each owner gets one equal vote only when every assessment is the same size. Only valid ballots received by the end of the hearing count. If more than 50 percent of the ballots cast oppose the district, the proceedings must be abandoned. That rule comes from Proposition 218. In the state's own text, ballots are "weighted according to the proportional financial obligation of the affected property," as reproduced by the Legislative Analyst's Office.
Two things follow for someone buying in. A parcel that carries more of the cost carries more of the vote. And the vote decides things for everyone in the boundary. Town Manager Greg Chanis put it plainly to the Marin IJ:
"If more than 50% of the property owners in the district approve, there's nothing stopping council from forming the district. Folks who vote against it are part of the district whether they vote no or yes."
Whoever owns the home on the day ballots are counted holds that weighted vote. A buyer who closes before the hearing gets the vote too, along with whatever the engineer's report says the parcel owes.
The assessment notice only applies after there's a lien
This is where the timing matters most. California's main disclosure rule here, Civil Code §1102.6b, applies to property already subject to "a fixed lien assessment collected in installments" for Improvement Bond Act of 1915 bonds, among other charges. For those homes, the seller has to make a good-faith effort to get the agency's notice and give it to the buyer. The same section says it imposes no "duty to discover a special tax or assessment installments or the existence of any levying district not actually known to the agents."
The notice itself is set out in Government Code §53754. It's built around "the annual assessment installment against this property as shown on the most recent tax bill." It lets the buyer cancel within three days if the notice was handed over in person, or within five days of mailing. A proposed district has no installment and nothing on a tax bill, so there's nothing to fill in.
That doesn't make a proposed district a secret. The California Department of Real Estate's reference book lists "Current, pending or proposed special assessments" among the typical things a seller represents to the listing broker. The DRE's Disclosures in Real Property Transactions also says agents must disclose "all material facts affecting the value, desirability, and intended use" of a property that they know or should know about. What a pending district doesn't come with is the state's standardized notice, which needs a dollar figure.
| Where the sale lands | What exists on paper | What a buyer can actually learn |
|---|---|---|
| Now, before the engineer's report | Council resolutions and a preliminary map | Whether the parcel is inside the boundary |
| After the Notice of Proposed Assessments | A proposed dollar figure for each parcel | The proposed share, plus a vote still to come |
| After an approving vote | A confirmed assessment and a recorded lien | The amount, with a cash-payment window of at least 30 days |
| After bonds go on the tax bill | A §53754 Notice of Special Assessment | The annual installment and the right to cancel |
Only the last row matches what the state's notice form expects. Mar West is in the first.
Tiburon's own history shows what an estimate can turn into
The policy's timeline, and every estimate the engineer produces, comes with an asterisk. Tiburon's earlier districts show why.
Del Mar Valley residents started organizing in 2003, and the town formed the 221-home district in 2005, according to a 2010 Town of Tiburon newsletter. Construction bids came back well above the money available. In 2006, the Marin IJ reported that owners voted to add $3.2 million to the $4.7 million already approved. That put a supplemental assessment of $7,700 to more than $20,500 per owner on top of an original assessment of $10,000 to more than $31,000, to be repaid over 30 years. The same article said Lyford Cove's supplemental assessment, approved that March, raised that project's cost by more than 50 percent. All of those figures are about 20 years old. They show how a final bill can drift from its estimate. They don't predict what Mar West will cost.
Del Mar then spent years in court. The town's newsletter describes three related lawsuits, an appellate ruling that the district's way of splitting costs violated Proposition 218, and a settlement that rebuilt the district and held a new vote on the supplemental financing. The settlement costs included $605,000 in plaintiffs' attorney fees and repayment with 5 percent interest to owners who were left out of the rebuilt district.
Things can also go the other way. In October 2024, the council approved roughly $838,000 in surplus refunds to members of the Hawthorne undergrounding district, which covers 120 homes and businesses, The Ark reported. Overruns and refunds both come out of the same process, and both land on whoever owns the home when the money moves.
What the bill looks like once it's real
If Mar West does form, the policy lays out how owners pay. Each assessment can be paid in cash or bonded at tax-exempt municipal rates for 20 to 25 years. Bonded assessments are collected on the county tax bill. They are "not a personal obligation of the property owner," and they pass with title "like regular taxes." Marin County's guide to the secured tax bill shows these charges in their own section, added to the value-based tax. The county's property tax FAQ says to call the taxing agency at the number printed next to the charge for details.
The assessment also leaves one cost out. Each owner pays to connect their own house to the new underground lines, and that's typically not part of the assessment. A small amount of bond money may be set aside, first come, first served, to help with connections. A buyer comparing a Mar West home with one outside the boundary is comparing two numbers, and one of them doesn't exist yet.
Not everyone on the council likes how the state's system works. Councilmember Holli Thier voted for the resolutions and still told the Marin IJ, "I believe PG&E should be paying this cost." The process is governed by state law, so Mar West will follow the same steps the policy describes.
A short FAQ
If I buy before the vote, do I get a ballot? Ballots go to property owners and are counted at the hearing, weighted by dollars assessed. Whoever owns the parcel at that point holds its share of the vote.
Can I get an official assessment notice for a Mar West home today? Under §53754, the agency's designated office has to provide a Notice of Special Assessment within five working days of a request and can charge up to $10. That notice covers installments already levied to repay bonds. A proposed district hasn't reached that stage.
What happens to the money spent so far if the district fails? The town's share of the design costs is lost if the district doesn't form, and it's repaid from bond funding if it does.
This post is general information, not legal, tax or financial advice. If an assessment district touches a home you're buying or selling, confirm the details with the Town of Tiburon and the right professional.
If you're thinking about buying or selling on Mar West Street, Esperanza Street or Las Lomas Lane while the district is still in the works, Marc Machado can walk you through where it stands and what to ask before you sign. Reach Out Today.
