Diamond Bar HOA Guide: Local Rules for Boards and Owners

The city says short-term rentals are not allowed in residential zones. Its reasoning: the municipal code treats lodging for stays of less than 30 days as a hotel or motel use, and that use is not permitted in residential zones. The city cites Municipal Code sections 22.08.030 and 22.80.020.

Because there is no city permit, the question of HOA permission does not come up. Your CC&Rs can still add their own rental limits. Questions go to Neighborhood Improvement at (909) 839-7030.

Diamond Bar has a tree preservation chapter, Municipal Code Chapter 22.38. We could not open the city’s code. The only text we could read was an undated excerpt hosted on a Los Angeles County site, and the latest amendment it cites is from 2003. Treat the points below as a guide and confirm the current chapter with the city before you cut, prune or remove anything.

• Protected trees are native oak, walnut, sycamore and willow of 8 inches or more in trunk diameter, plus trees preserved or planted as a permit condition.
• Cutting, removing, relocating or topping a protected tree is prohibited without a permit.
• Pruning branches over 4 inches needs a pruning permit, and pruning is capped at 20% of a tree and 10% of an oak.
• Exemptions include hazards verified by an arborist, emergencies and pruning of branches 4 inches or smaller.
• Replacement is generally 2 to 1 on residential lots under 20,000 square feet and 3 to 1 on larger lots.

The excerpt does not say how the chapter applies to HOA common areas. Ask the city.

Separately, the city’s property maintenance guide says dead, decayed or diseased trees are not permitted. It also says hedges, trees and shrubs may not overhang sidewalks, parkways, curbs or streets in a way that blocks vehicles, pedestrians or drainage. The city trims parkway trees, and Public Works takes requests at (909) 839-7060.

These rules come from the city’s property maintenance guide, which cites the code sections:

• A vehicle may not stay on a city street more than 72 hours without being moved.
• Commercial vehicles over 10,000 gross pounds may not stop or park on residential streets except for pickup or delivery.
• On private property, commercial vehicles, trailers and equipment may not be parked or stored more than 72 hours, except where construction is under way. The limit is two commercial vehicles or trailers per parcel.
• Licensed vehicles, trailers and boats must sit on a garage, carport, concrete or asphalt driveway or other approved all-weather surface. Parking on landscaped areas is prohibited.
• Inoperable vehicles may not be stored in public view or left on city streets.
• In rear yards, licensed boats and trailers must be screened by approved walls or fences.

Street sweeping limits parking on each neighborhood’s sweeping day, and a vehicle that blocks the sweeper can be cited. Pay or dispute tickets with the Citation Processing Center at (800) 989-2058.

We could not confirm whether the city enforces parking on private HOA streets, and we found no RV-specific rule. The city’s pages do not say. Ask Public Works at (909) 839-7060 before you rely on the city to tow from a private street.

Under Municipal Code section 22.34.030(d)(1)(a), as the city describes it, slopes next to a public street must be kept neat and clean, free of weeds and debris. Unless an HOA or a Lighting and Landscape Assessment District maintains a slope, each owner must maintain it and its drainage devices. The city page names no specific districts, so check your tract documents.

The city’s slope guidelines include clearing drainage ditches before winter, planting deep-rooted, drought-tolerant, fire-retardant groundcover and not sending water over the top of a slope. Avoid ice plant. Grading repairs often need engineering and may need a city permit. City vegetation requirements go beyond the County Fire brush clearance rules.

Call Neighborhood Improvement at (909) 839-7030 or Engineering at (909) 839-7040.

The Walnut Valley Water District serves Diamond Bar, plus parts of Industry, Pomona, Walnut and West Covina and part of unincorporated Rowland Heights. Its page does not say whether all of Diamond Bar is inside the district, so confirm your address.

The district’s drought page describes a Stage 2 Water Shortage with a mandatory 20% use reduction. The page is undated, so ask the district whether that stage is still in effect before you set a schedule. The limits it lists:

• Watering at most 3 days a week, not between 8 a.m. and 5 p.m., and no more than 15 minutes per station per day.
• No watering with tap water for 48 hours after measurable rain, and no runoff onto streets, driveways, sidewalks or gutters.
• Exempt: very low-flow drip systems from the day and time limits, high-efficiency sprinklers from the 15-minute limit, and hand-held buckets.
• No irrigating ornamental turf or street medians with drinking water, no hosing vehicles without a shutoff nozzle and no non-recirculating fountains.
• Leaks must be fixed within 72 hours of written notice.

Penalties are set in the district’s ordinance, and the page lists no amounts. For rebates, the residential page lists turf replacement at $3 or more per square foot, capped at 5,000 square feet, and device rebates through SoCal Water$mart. The commercial page names no HOA or common-area program, so we could not confirm one. Customer service is at (909) 595-7554.

Annual defensible space inspections are done by the Diamond Bar fire stations (Los Angeles County Fire) and begin May 1 each year. They focus on designated brush areas and high fire hazard severity zones. Owners must clear native vegetation and maintain ornamental vegetation. The city’s page does not mention HOAs.

The State Fire Marshal released recommended updated fire hazard maps. The city says County Fire had until June 24, 2025 to adopt them, and does not confirm that it did. The city has posted a PDF of Diamond Bar’s new zones in its Document Center. High and very high zones may be subject to state building and defensible space rules.

On private property, weed and sanitation enforcement is done by the city’s Neighborhood Improvement officers working with County Fire. We found no abatement deadlines. The County Fire inspection details PDF would not open, so call the city at (909) 839-7000 for current dates and distances.